IRLF 


31    fllfl 


THE 


LEATHER  MANUFACTURE 


:>T  THE 


UNITED    STATES; 

A  DISSERTATION  ON  THE  METHODS  AND 
ECONOMIES  OF  TANNING. 


BY  JACKSON  S.  SCIIULTZ. 


WITH  NtJMBBOUa  ILLUSTRATIONS. 


TO   WHICH   IS  ADDED   A  REPORT  ON  THE  RELATIVE   ECONOMIES  OF 
BURNING  WET  SPENT  TAN,   BY  THERON  SKEEL,  C.  E. 


NEW  YORK: 
"  SHOE  AND   LEATHER  REPORTER  "    OFFICE, 

1876. 


Entered  according  to  Act  of  Congress,  in  the  Year  1876, 

BY  ISAAC  H.  BAILEY, 
In  the  Office  of  the  Librarian  of  Congress,  at  Washington. 


MIINTKD  AND  SrEHEOTYPKD  BV 
ISAAC  H.  BAILEY, 
.!•<•£  ST.,  NEW  YORK. 


PKEEAOE. 


The  proprietor  of  the  SHOE  AND  LEATHER  REPORTER  pro- 
poses to  meet  a  very  general  demand  for  information  in 
regard  to  the  manufacture  of  bark  tanned  leather  by  group- 
ing together  in  permanent  form  a  series  of  articles  on  the 
subject,  written  for  the  paper  by  Mr.  JACKSON  S.  SCHULTZ. 
To  make  the  work  acceptable  to  the  tanners,  not  only  of 
Ameiiaa  but  of  foreign  countries,  it  will  be  appropriately 
illustrated,  presenting  in  outline,  and  in  some  instances  in 
working  drawings,  the  principal  mechanical  inventions  em- 
ployed in  the  business,  so  that  the  machines  may  be  dupli- 
cated and  the  methods  of  their  use  easily  comprehended. 
It  was  found  inconvenient  to  illustrate  the  work  during  its 
publication  in  serial  numbers,  but  now  that  it  is  to  appear  in 
book  form  that  feature  will  be  supplied,  and  will  add  to  its 
appearance  and  usefulness. 

If  the  undertaking  should  be  adequately  encouraged  by 
the  tanners  and  finishers  of  bark  leather,  it  will  be  followed 
at  an  early  day  by  essays  treating  of  "  Sumac  Tanning,"  and 
such  other  departments  of  leather  and  its  fabrics  as  may  be 
deemed  worthy  of  consideration. 

NEW  YORK,  July,  1876. 


M134583 


CONTENTS. 


PAGE. 
INTRODUCTION,          -  -  xni 

CHAPTEK    I. 

SELECTION  AND  CLASSIFICATION  OF  HIDES  AND 

SKINS. 

SIMILARITY    OF   STOCK    AS   TO     WEIGHT,    SUBSTANCE     AND    CONDITION, 

HIGHLY  IMPORTANT ASSORTING  IN  THE  SOAK  AND  HIDE   MILL 

HIDES  SHOULD  BE  OF  EQUAL  CONDITION  ON  ENTERING  THE  HAND- 
LERS  BREAKING   THE   NERVE  IN   CALF,  KIP  AND  UPPER  LEATHER 

IMPOLICY  OF   "WORKING  SEVERAL  KINDS  OF   HIDES  IN  ONE  YARD 

AT  THE  SAME  TIME.      -  -  ...      17 

CHAPTEE    II. 
PREPARATION  OF  HIDES  FOR  THE  BARK— SWEATING. 

COLD   AND  WARM   SWEATING CONSTRUCTION  OF   SWEAT   PITS CLEAN- 
LINESS, LIGHT  AND  IMPENETRABILITY  TO  AIR   NECESSARY  IN  COLD 

SWEAT  PITS PROPER  CONDITION  OF  STOCK  BEFORE  ENTERING  THE 

PITS CARE   NECESSARY  IN  THE  SWEATING   PROCESS TREATMENT 

AFTER  THE  HIDES  COME  FROM  THE  PITS PART  LIMING  AND  PART 

SWEATING GREASE  AND  SALT  ON  HIDES.  -  -  -      23 

CHAPTEE    III. 
PREPARATION   OF   HIDES   FOR    THE   BARK— LIMING. 

GETTING   READY  THE   LIMES THEIR  AGE  AND   STRENGTH EFFECT   OF 

THE  LIME  ON   THE   FIBER PLUMPING   AND    BATING PROF.  LUF- 

KIN'S    PROCESS THE    "BUFFALO"    METHOD THEIR    RESULTS 

HANDLING  IN  THE  LIMES.      -------31 


VI  CONTENTS. 

CHAPTER    IV. 

PREPARATION  OF  HIDES  FOR  THE   BARK— FLESHING 
AND  TRIMMING. 

THE   BEAM    WORK CLOSE    FLESHING,  WITHOUT    BREAKING    THE    GLUE 

CELLS — FLESHING   LIME   SLAUGHTER   STOCK WORK  TO  BE   DONE 

BEFORE   LIMING FLESHING  SWEAT   STOCK IT  SHOULD  BE   DONE 

WITH     A    WORKER THE     GERMAN     FLESHER TRIMMING CROP 

LEATHER    AND    BACKS ADVANTAGES     OF     TRIMMING    UPPER    AS 

WELL    AS    SOLE "ROUNDING" TRIMMING    BEFORE    TANNING 

BEST  METHOD  OF   UTILIZING  THE  HEAD,  PATE,  ETC.       -          -          -      38 

CHAPTER    Y. 
GRINDING  BARK— BARK  MILLS. 

THE  INEXPENSIVE  AND  ABUNDANT  POWER  OF  SOLE  LEATHER  TANNERIES 
GRINDING  BARK  FINE  AND  UNIFORM USEFULNESS  OF  SCREEN- 
ING THE  GROUND  BARK THE  DOUBLE-GRINDING  MILL ITS 

EFFECTIVENESS    WITH    DAMP    BARK THE    ALLENTOWN    MILL 

ADVANTAGE  OF   A  STRONG  MILL  AND  A  WEAK  COUPLER THE  SAW 

CUTTING  MILL A  BARK  CRUSHING  MACHINE THE  PROPER  SPEED 

AT  WHICH  MILLS  SHOULD  BE  RUN TANNIN  LEFT  IN  THE  BARK.    -      46 

CHAPTER    VI. 
LEACHING. 

TANNIN  VS.  RESINOUS  AND  COLORING   MATTER TANNIN   REQUIRED    TO 

MAKE  GOOD  WEIGHT EXTREME  HEAT  IN   LEACHING  INJURIOUS 

FLOODING  THE  BARK THE  PRESS   LEACH HEAT   TO   BE   APPLIED 

ONLY   TO    THE  WEAKEST    LEACH CONSTRUCTION    OF    LEACHES 

CLAY  AND  LOAM  PACKING   FOR  THE   SIDES  AND   BOTTOMS WORK- 

ING  THE  PRESS  LEACH THE  SPRINKLER    LEACH REVOLVING  DE- 

TAGHED  LEACH.  -  V          .  .  -      55 

CHAPTER    VII. 
HANDLING. 

THE    HAND     BEET. THE    ROCKER    HANDLER ITS    CONSTRUCTION    AND 

OPERATION IMMERSED    DRUM  WHEELS A   METHOD    OF    RAISING 

HIDES   FROM  THE   HANDLER   VATS THE  TUB  WHEEL    HANDLER 

HANGING  HIDES   IN  THE  HANDLERS THE    "  ENGLAND  "    WHEEL 

HANDLING  WITH  THE  COX  ROLLERS.  -----      G8 


CONTENTS.  Vll 

CHAPTEE    VIII. 
HANDLING  AND  PLUMPING. 

THE   USE   OF   VEGETABLE   AND     MINERAL    ACIDS THE   EAELY    USE    OF 

VITRIOL  BY  AMERICAN  TANNERS CONSIDERATIONS  AFFECTING  THE 

AMOUNT  WHICH  MAY  BE  USED ITS  EFFECT  ON  LIMED  AND  SWEAT 

STOCK STRENGTH   AND    AGE    OF    LIQUORS   TO    BE    USED    IN    THE 

HANDLERS DIFFERENCES  IN    THE   HANDLING    AND    PLUMPING  OF 

SOLE  AND  UPPER  LEATHER.  --....      76 

CHAPTEE    IX. 
LAYING    AWAY. 

TIME     REQUIRED     AND     STRENGTH      OF     LIQUOR    WHICH     SHOULD     BE 

EMPLOYED TANNING    IN    THE    HANDLERS    VS.    LAYING    AWAY 

EUROPEAN  METHODS "  BLACK  ROT  "    AND   WHITE  SPOTS THEIR 

CAUSES  AND  THE  REMEDIES SHOULD  HIDES  BE  LAID  AWAY  GRAIN 

UP  OR  FLESH  UP  ?— MAKING  WEIGHT  IN  THE  LAST  LAYER.        -      -      84 

CHAPTEE    X. 
DKYING  AND  FINISHING. 

BEING  THE    LEATHER THE  "  HOWAT 

WHEEL  OR  DRUM  SCRUBBING DRAINING HOW  THE  ADMISSION 

OF  LIGHT  AND  AIR  SHOULD  BE  REGULATED  IN  DRYING DAMPENING 

BEFORE  ROLLING THE  FIRST  AND  SECOND    ROLLING EFFECT  OF 

THE    ROLLING    ON   THE    BUFFING     QUALITIES BLEACHING    WITH 

SUGAR    OF   LEAD    AND  SULPHURIC   ACID THE  WARM  SUMAC  BATH 

EFFECT  OF  THE  LATTER  ON  CALFSKINS,  GRAIN  LEATHER,  ETC.  -      94 

CHAPTEE    XI. 

THE  CAUSES  WHICH  AFFECT   COLOK  AND  ASSIST  IK 
THE  MAKING  OF  A  VALUABLE  EMBOSSING  GEAIN. 

WHY  LEATHER   SHOULD  BE    THOROUGHLY    DRIED STRUCTURE    OF   THE 

GRAIN IMPORTANCE  OF  A  PERFECT    FINISH CARE  TO  BE  TAKEN 

TO    AVOID     STAINS    AND    DISCOLORATION "  CUIR  "  COLOR — THE 

NATURAL  HEMLOCK  COLOR "  RUSSIA  LEATHER  "  COLOR — FRAUDS 

IN  SELLING  HEMLOCK  FOR  OAK  LEATHER  DURING  THE  WAR COL- 
ORING TO  BE  DONE  IN  THE    HANDLERS EFFECT  OF  "  STRIKING  " 

THE  GRAIN.  ------    103 


viii  CONTENTS. 

CHAPTER    XII. 

CONSTRUCTION  OF  TANNERIES— THE  TURRET  DRYER. 

v 

HOW  THE  ADMISSION  OF  LIGHT  AND  AIR  IS  CONTROLLED  IN  THE  TURRET 

DRYER ITS    CAPABILITIES    FOR    DRYING    LEATHER    IN     QUICKER 

TIME,  WITHOUT  REGARD  TO    THE   WEATHER ITS    CONSTRUCTION, 

AND  HOW  ITS   CAPACITY   SHOULD  BE   PROPORTIONED    TO  THAT    OF 

THE  YARD HOW   AND   WHEN    HEAT    SHOULD    BE   USED HOW    TO 

PREVENT  DISCOLORATION  OF  THE  LEATHER SAVING  OF  LABOR  IN 

THE  TURRET  DRYER.  -  -  -  -  -    110 

CHAPTER    XIII. 

CONSTRUCTION  OF   TANNERIES— PLANS,  FOUNDA- 
TIONS, ETC. 

THOROUGH  EXAMINATION    OF    PRESENT    f.TErCTURES   AND    APPLIANCES 
ADVISABLE    BEFORE    BUILDING — IT.irOKTANT    CHANGES   FROM  THE 

PRESENT    GENERAL    USE    OF   STEAM   INSTEAD  OF  WATER  POWER 

LOCATING  ON    "  MANUFACTURING  "  AND  "  CULINARY  "  STREAMS 

A    LOAM,    CLAY,    OR    SANDY    FOUNDATION FILLING    IN  BETWEEN 

VATS  AND   LEACHES  WITH   LOAM  OR    CLAY PLACING  THE  VATS 

THE    "  BUFFALO  "    VAT "  BOX  "  VATS THE  PROCESS    OF    "  PUD- 
DLING "    IN   SETTING   THE   VATS UPPER  CONDUCTORS SIDE  AND 

END    WALLS.  -  -  117 

CHAPTER    XIV. 

i 

CONSTRUCTION   OF   TANNERIES— LEACHES. 

ROUND  OR  SQUARE  LEACHES THE  DURATION    OF   LEACHES  ABOVE   AND 

SUNK  IN  THE  GROUND HOW  TO  BUILD  A  ROUND  LEACH HOW  TO 

MAKE  AND  SET  LEACHES  IN  THE  GROUND THE   CAPACITY  OF  THE 

SETS  OF  LEACHES  TO  BE  PROPORTIONED  TO  THE  SIZE  OF  THE  TAN- 
NKRY.  -    126 

CHAPTER    XY. 

CONSTRUCTION   OF   TANNERIES— FRAME  WORK   A1TD 
LOCATION  OF  BUILDINGS. 

WHY  THEY  SHOULD  BE  ONLY  ONE-STORY  HIGH  FOR  THE  YARD  AND  BEAM 

HOUSE SAV  NG  IN  INSURANCE    BY  SEPARATING  THE  BUILDINGS 

CONVEYING  LEATHER  TO   THE  "  TURRET  "  DRYER TRANSMITTING 


CONTENTS.  IX 

POWER  TO  DISTANT   BUILDINGS PROPER   SPEED   FOP.  BARK  MILLS 

AND  ELEVATORS SIMPLE  PROVISIONS  AGAINST  FIRE  AND  BREAK- 
AGE, AND  TO  PREVENT  DUST.  -  -  134 

CHAPTEE    XVI. 
THE  BOSSING  OF  BAEK. 

THEORIES  OF  THOSE  WHO  ADVOCATE  ROSSING ITS   COST DIFFICULTY 

OF  ROSSING    WITHOUT    TOO    GREAT  LOSS   OF   TANNIN STRENGTH 

OF  LIQUORS  WHICH  MAY  BE  OBTAINED  FROM  ROSSED  AND  UN- 
ROSSED  BARK POSSIBLE  ADVANTAGE  IN  ROSSING  BARK  FOR  EX- 
PORT IN  THE  "  LEAF."  -  -  141 

CHAPTEE    XVII. 

UTILIZATION  OF  TANNEEY  REFUSE. 

BURNING  THE  WET  TAN GLUE  STOCK IMPORTANCE    OF  KEEPING  THE 

PIECES  PURE   AND    SWEET PRESERVING,    CLEANSING  AND  DRYING 

THEM — USES  FOR  CATTLE  HAIR THAT  WHICH  COMES  FROM  SWEAT 

OR  LIMED  STOCK WASHING,  DRYING  AND  PACKING FERTILIZING 

LIQUIDS  FROM  THE  LIMES   AND  SOAKS.  -  -   14(j 

CHAPTEE    XVIII. 
TANNING     MATEEIALS. 

DIFFERENT   KINDS    OF    HEMLOCK    BARK INFLUENCE  OF  SOIL  AND  CLI- 
MATE ON  THE  QUALITY HEAVY  AND  LIGHT  BARK VARIETIES  OF 

OAK  BARK THE  "  SECOND  GROWTH  "  BETTER  THAN  THE  FIRST 

GAMBIER ITS    GROWTH    AND     PREPARATION    FOR    MARKET ITS 

COST  COMPARED  WITH  THAT  OF  BARK VALONIA,  DIVI DIVI,  MYRA- 

EOLAMS "  SWEET  FERN,"  ETC.  -  -    155 

CHAPTEE    XIX. 
THE    COST    OF    TANNING. 

THE  SEVERAL  ITEMS  VARYING  WITH  DIFFERENT  TANNERS DIFFERENCES 

FROM  UNEQUAL  WEIGHT  OF  THE  CORD  OF  BARK THE  AMOUNT 

OF  TANNIN  IN  UPPER  LEATHER  AS  COMPARED  WITH  THAT  IN  SOLE 

LEATHER COMPARATIVE  COST  IN  MAKING   HEAVY   AND   LIGHT 

GAINS THE  THEORETICAL  STRENGTH  OF  BARK  NEVER  REALIZED 

— COST  OF  "UNION"  AND  OAK  TANNING — ESTIMATED  COST  OF 

TANNING   IN   EUROPE.  -----   169 


x  CC:;TL:;TS. 

CHAPTEE    XX. 
QUICK  TANNING  PROCESSES. 

COMMON  ERRORS  OF  THOSE  OUTSIDE  OF  THE  TRADE — HOW  WORTHLESS 
PATENTS  ARE  MULTIPLIED EXPERIMENT  IN  TANNING  BY  HYDRO- 
STATIC PRESSURE VACUUM  TANNING — DIFFICULTIES  ATTENDING 

THIS  METHOD HOW    AGITATION    OF  THE  FIBER  FACILITATES  THE 

PROCESS A  GENTLE  MOVEMENT,    WITH    OCCASIONAL    REST,    MOST 

EFFICACIOUS TANNING    VS.    TAWING.  -  176 

CHAPTEK    XXI. 
THE  SPECIES  AND  GROWTH  OF  HIDES. 

"  HEALTHY  "  AND  "  WELL  GROWN  "  HIDES DIFFERENCES  IN  HIDES   AT 

VARIOUS  SEASONS  OF  THE  YEAR EFFECT    OF   CLIMATE  AND  FOOD 

ON  TEXTURE  AND   GROWTH IMPROVED   BREEDS  OF  CATTLE  MAKE 

HIDES  THIN  AND  SPREADY COLD  CLIMATE  MAKES  A  COARSE  FIBER 

AND  WARM    CLIMATE    A    FINE    TEXTURE EAST    INDIAN,    AFRICAN 

AND  SOUTH  AMERICAN  HIDES — THE  HIDES  FROM  THE  EASTERN 
AND  MIDDLE  STATES  AS  COMPARED  WITH  THOSE  FROM  THE  WEST- 
ERN PRAIRIES — CARE  TAKEN  OF  CATTLE  IN  EUROPE.  -  -  188 

CHAPTEE    XXII. 
FRENCH  AND  GERMAN  CALF  AND  KIP. 

WHERE  OUR   IMPORTED    STOCK    COMES    FROM CAREFUL  ASSORTING  OF 

THE  RAW  STOCK  TO  INSURE    UNIFORMITY    IN  WEIGHT,  SUBSTANCE 

AND    GEN7ERAL    CONDITION SOAKING    AND    MILLING BREAKING 

THE  NERVE LIMING BATING  AND  WORKING  OUT  LIME COLOR- 
ING AND  HANDLING LAYING  AWAY  AFTER  WORKING STUFFING 

DRYING SLICKER    WHITENING BLACKING    AFTER   THE   STOCK 

IS  CUT  OUT  USUAL  IN    EUROPE VEGETABLE    OILS   USED    INSTEAD 

OF  FISH  OILS DEFECTS  IN  FOREIGN  CALFSKINS — -STEADY  IM- 
PROVEMENT IN  AMERICAN  CALFSKINS.  -  -  194 

CHAPTEE    XXIII. 
GRAIN  AND  BUFF  LEATHER. 

SPLITTING  MACHINES MAKING    SPLIT    LEATHERS    FROM    GREEN  HIDES 

OR    FROM    TANNED    LEATHER EVERY  KIND   OF    NATURAL    GRAIN 

SUCCESSFULLY  IMITATED STRENGTH    AND    DURABILITY    OF  SPLIT 


CONTENTS. 

LEATHERS THEIR  INTRODUCTION  TO  EUROPEAN  CONSUMERS ES 

SENTIALS   TO    BE    CONSIDERED    IN   THE    MANUFACTURE   OF   GRAIN 
AND  BUFF  LEATHER.  ~  '   210 

CHAPTEE    XXIY. 
CUBRYING  AND  FINISHING. 

THE  STUFFING  WHEEL  AND  HOW  TO    USE   IT TO  PURIFY  AND  CLEANSE 

DIRTY    GREASE HOW    TO   MAKE  STUFFING FLESH    BLACKING 

FLOUR  AND  SIZE  PASTES— HARM  THAT  MAY  BE   DONE  BY  DEPEND- 
ENCE UPON   RECIPES DAMPENING    LEATHER    BEFORE    AND  AFTER 

APPLYING  OIL  AND  TALLOW.    - 

CHAPTEE    XXV. 

DIRECTIONS   FOR   THE     CONSTRUCTION     OF    DETACHED    FURNACES    FOR 
BURNING  WET  SPENT  TAN,    BY  THERON  SKEEL,  C.  E.    - 


LIST   OF   ILLUSTRATIONS. 

PAGE. 

COLD  SWEAT  PITS,  -  -  249 

HIDE  MILL,        -  -       251 

HAND  REEL,  -                                    -  -                  -            253 

ROCKER  HANDLER,       -  -       255 

SOLE  LEATHER  ROLLER,  -  -  257 

TURRET  DRYER,  -  -       259 

SPRINKLER  LEACH,  -  -         -  261 

BARK  CUTTING  MILL,  -  263 

ALLENTOWN  BARK  MILL,  -  265 

HOWARD   LEATHER  WASHER,  -       265 

SALEM  TAN  PRESS,  -  -  267 

LOCKWOOD   LEATHER  SCOURER,     -  269 

FITZHENRY  LEATHER  SCOURER,  -  -  271 

BURDON  LEATHER  SCOURER,  -  273 

STUFFING  WHEEL,  -              r  -  -  275 

CHARLES  KORN'S  WHITENER,  -       277 

UNION  WHITENER  AND  BUFFING  MACHINE,  -  279 

FISK'S  WHITENER  AND  BUFFING  MACHINE,  -..,                -        -       281 

UNION  LEATHER  SPLITTER,        -'  -  283 

HENRY  LAMPERT'S  HIDE  WORKER,  -      283 

OUTLINE  AND  TRIM  OF  HIDE,    «•     .  .-  -                           -  285 

TANNERS'  AND  CURRIERS'  TOOLS,    -  -       287 

HOYT  FURNACE  AT  WILCOX  PENN.,  PLATES  I,  II,  HI,   -    289,  291,  293 

DESIGN  FOR  WET  TAN  FURNACE,  PLATES  IV,  V,  VI,  -  295,  297,  299 


I-NTBO'DUCTION. 


This  Centennial  year  seems  an  appropriate  periol  in  which 
to  review  the  progress  and  present  attainment  of  the  tanner's 
art  in  America.  In  the  chapters  which  are  to  follow  it  is 
not  proposed  to  give  a  chronological  history  so  much  as  the 
general  progress  of  the  trade,  and  even  that  progress  will  be 
considered  in  subordination  to  the  permanent  advance- 
ment of  the  whole  manufacture,  rather  than  to  the  glorifica- 
tion of  any  special  period  of  our  trade  history,  or  the  com- 
mendation of  any  particular  man  or  class  of  men,  however 
conspicuous  they  may  have  been  daring  critical  periods. 
This  purpose  will  mike  it  unnecessary  to  inquire  whether 
"  Simon  "  was  a  good  or  poor  tanner  ;  indeed,  whether  hs 
was  a  tanner  at  all,  since,  whatever  his  merits  as  an  artisan, 
they  have  long  since  been  surpassed  by  others  with  far 
better  methods. 

For  similar  reasons  no  attempt  will  be  made  to  bring  un- 
der review  the  various  exploded  patents  and  so-called  im- 
provements that  have  for  the  past  fifty  years  been  pressed 
on  the  attention  of  tanners.  No  volume,  however  large, 
would  be  adequate  to  contain  the  recital  of  their  origin  and 
pretensions.  But  so  many  of  such  improvements  as  have 
been  at  any  time  adopted  by  any  considerable  number  of  the 
trade — and  particularly  if  they  have  a  practical  existence  in 


XIV  INTRODUCTION. 

any  of  our  modern  yards — will  receive  respectful  considera- 
tion. This,  to  be  useful,  must  be  candid,  and  free  from  ail 
bias. 

To  intelligently  contrast  the  merits  of  mechanical  inven- 
tions— to  hold  an  even  hand  in  weighing  the  advantages  and 
disadvantages  of  systems  and  methods  which  include  among 
their  advocates  men  equally  intelligent — is  a  task  not  likely 
to  be  accomplished  without  involving  the  writer  in  much  cen- 
sorious criticism.  But  if  an  entire  absence  of  all  ownership 
or  interest  in  patented  or  other  improvements  can  qualify 
one  for  the  task,  then  these  chapters  will  contain  a  fair 
presentation  of  the  merits  of  all  claims. 

The  form  chosen  in  which  to  present  this  subject  is  intended 
to  elicit  honest  inquiry  and  full  discussion.  Instead  of  a  treatise 
giving  in  dogmatic  language  the  processes  which  it  is  claimed 
tanners  have  adopted  or  must  adopt,  it  is  intended  here  to  pre- 
sent the  merits  and  defects  of  known  systems  and  methods  as 
their  advocates  would  state  them,  and  hold  these  up  in  contrast 
with  other  methods  commended  by  equally  intelligent  men, 
and  thus,  by  candid  comparison,  show  their  relative  merits, 
and  indicate  such  preference  as  may  appear  to  be  justified  by 
our  experience.  This  course  of  inquiry  and  presentation 
will,  it  is  believed,  lead  to  far  better  results  than  if  precon- 
ceived and  fixed  theories  and  opinions  were  enunciated  and 
defended.  In  still  other  words,  these  chapters  will  contain 
a  tolerant  discussion  of  the  present  condition  of  the  tanner's 
art  in  America,  and,  by  way  of  contrast  and  honorable  emu- 
lation, with  the  relative  position  of  the  same  trade  in  the 
more  advanced  nations  of  Europe,  and  in  the  treatment  of 
these  subjects  there  will  be  no  pedantic  use  of  terms,  either 
mechanical  or  otherwise ;  only  such  phrases  and  words  will 
be  employed  as  are  familiar  to  all  practical  tanners. 

While  it  is  conceded  that  the  tanner's  art  is  largely  chemical 


INTRODUCTION.  XV 

in  its  nature,  and  may  in  the  future  be  greatly  advanced  by 
the  study  and  application  of  chemical  laws,  in  this  prelimi- 
nary inquiry  it  is  thought  expedient  for  both  writer  and 
reader  to  confine  attention  to  the  tanner's  art  as  understood 
by  ordinary  workmen. 

It  is  proposed  here  to  treat  only  of  the  subject  of  "  tan- 
ning" as  contradistinguished  from  "tawing."  The  art  of 
"  tanning  "  differs  so  widely  from  that  of  "  tawing  "  that  an 
expert  in  the  one  maybe  a  novice  in  the  other.  They  do  not 
assimilate  any  more  than  the  glove  maker  does  with  the  boot 
or  shoe  maker.  The  latter  uses  "  tanned,"  while  the  former 
uses  "  tawed  "  leather.  Sir  Humphrey  Davy  has  drawn  the 
distinction  by  the  adoption  of  a  chemical  formula  and  test. 
He  says,  in  substance,  that  leather  is  a  chemical  combination 
of  gelatine  and  tannin,  its  characteristic  being  that,  when 
combined,  wrater  will  not  separate  the  constituents  or  dissolve 
the  connection ;  whereas,  in  the  tawing  process,  water  will 
separate  them  and  return  the  gelatine  and  salt  or  alum  into 
their  original  elements. 

In  America  we  have  but  little  experience  with  any  other 
than  bark  tannage,  and,  therefore,  if  we  speak  at  all  of  the 
various  substitutes  for  bark  used  by  tanners  in  the  old  world, 
it  must  be  from  a  very  limited  experience  and  a  qualified 
knowledge.  In  deference  to  the  success  of  the  tanners  of 
Great  Britain  we  are  compelled  to  admit  that  vegetable  sub- 
stances other  than  bark — such  as  cutch,  terra  japonica,  valo- 
nia,  myrabolams,  divi  divi,  etc. — do  tan  leather.  These  ma- 
terials practically  do  the  tanning  for  Great  Britain,  and  make 
a  serviceable  and  even  artistic  leather.  The  barks  of  our 
forests,  particularly  those  of  the  hemlock  and  the  oak,  are, 
then,  only  two  among  the  tanning  agents  which  are  to  be  em- 
ployed in  making  leather.  But  as  these  are  the  agents  with 
which  we  are  most  familiar — indeed,  the  only  agents  in  gen- 


XVI  INTRODUCTION. 

eral  use  in  this  country — it  is  with  reference  to  their  use  that 
these  chapters  will  treat,  considering  only  incidentally  such 
other  tanning  materials  as  come  into  competition. 

The  only  exception  to  the  use  of  barks  or  bark  extracts  in 
this  country  is  that  of  "  terra  japonica,"  and  this  is  used  only 
to  a  limited  extent.  But;  as  this  tanning  substance  has  been 
the  innocent  cause  of  much  misapprehension,  and  has  led 
many  novices  into  grave  mistakes,  as  we  pass  along  we  may 
turn  aside  occasionally  to  point  out  this  rock  on  which  many 
hopes  and  even  fortunes  have  been  wrecked. 

In  illustrating  the  machinery  which  is  most  approved  by 
tanners  and  workers  in  leather,  it  must  be  understood  that  only 
such  kinds  are  here  presented  as  are  new,  or  comparatively  so, 
in  construction.  Many  useful  machines  are  now  in  use,  but 
so  old  and  familiar  that  it  is  not  thought  expedient  to  en- 
cumber these  pages  with  their  presentation.  Some  of  the 
illustrations  are  of  old  machines  with  new  attachments; 
whenever  this  occurs  an  attempt  will  be  made  to  designate 
the  added  novelty,  in  the  texj;  accompanying  the  drawing,  or 
in  the  drawing  itself. 


CHAPTEE    I. 

SELECTION  AND  CLASSIFICATION  OF  HIDES  AND 

SKINS. 

SIMILARITY   OF   STOCK   AS   TO   WEIGHT,   SUBSTANCE   AND   CONDITION,  HIGHLY 

IMPORTANT ASSORTING  IN  THE  SOAK  AND  HIDE   MILL HIDES   SHOULD 

BE  OF  EQUAL  CONDITION  ON  ENTERING  THE  HANDLERS — BREAKING  THS 

NERVE    IN    CALF,    KIP    AND    UPPER    LEATHER IMPOLICY    OF    WORKING 

SEVERAL  KINDS  OF  HIDES  IN  ONE  YARD  AT  THE  SAME  TIME. 

To  secure  the  bsst  results  throughout  the  tanning  and  fin- 
ishing of  leather,  there  must  be  equality  of  condition,  and  the 
conditions  must  be  favorable ;  among  these  conditions  are 
similarity  or  equality  of  stock  at  the  start.  Dry  flint  hides 
cannot  be  worked  with  salted ;  heavy  hides  cannot  be 
brought  into  condition  with  light  ones  in  the  same  pack. 
As  far  as  possible,  then,  both  as  to  weight,  substance  and 
condition,  the  pack  must  be  in  all  its  respects  equal.  Some 
tanners  think  they  effect  the  same  result  by  assorting  their 
packs  after  soaking,  or  after  milling  or  sweating  ;  but,  exer- 
cising all  the  judgment  that  is  possible  from  the  outset,  there 
will  be  opportunity  to  reject  and  assort  in  each  stage  of  the 
process. 

Where  it  is  possible  the  whole  lot  of  hides  should  be  clas- 
sified before  any  portion  is  put  into  the  soaks.  This  is 
not  always  convenient  or  possible — as,  for  instance,  where 
the  hides  are  brought  from  a  distant  depot,  sometimes  many 
miles  removed,  on  the  return  of  teams  from  delivering  loads  of 
leather  sent  away.  But  where  it  is  at  all  convenient  the 


18  THE  LEATHEK  MANUFACTURE. 

heavy  hides  should  be  selected  and  worked  in  first,  enabling 
the  whole  lot  to  come  out  at  the  same  time.  This  practice 
will  be  found  far  better  than  to  assort  the  packs  on  the  last 
layer,  throwing  the  heavy  sides  back,  and,  aside  from  the 
consideration  of  being  able  to  return  the  whole1  lot  promptly 
and  together,  it  enables  the  tanner  to  give  the  hides  better 
and  more  considerate  treatment  in  the  soaks,  mills  and 
sweats. 

After  classifying  all  hides  of  the  same  weight  and  general 
appearance  it  will  be  found  that  some  soften  much  more 
readily  than  others.  This  difference  will  be  discovered  gen- 
erally in  the  first  milling.  The  attendant,  standing  by  the 
side  of  the  mill  constantly,  with  his  hand  on  each  side  as  it 
•comes  round  in  its  turn,  will  "  draw  "  (remove)  the  soft  sides. 
'This  will  leave  the  hard  and  unyielding  sides  in  the  mill 
until  all  the  soft  ones  have  been  taken  out.  As  a  general 
•experience  it  will  be  found  inexpedient  to  "  force  "  these  re- 
maining sides.  It  is  better  that  they  be  taken  out  and  re- 
turned to  the  soak,  and  not  remilled  until  a  future  period, 
depending  on  the  weather  and  condition  of  the  water. 
"When  the  weather,  is  very  cold  these  hard  sides  may  be 
treated  to  a  batn*  of  moderately  warm  water — say  up  to 
80°  of  heat — for  a  few  hours.  If  they  are  sound  ihey  will 
usually  yield  on  the  second  milling. 

The  packs  should  not  be  formed  to  go  into  the  sweats 
until  after  they  have  come  from  the  mill.  The  experience 
gained  in  milling  will  enable  every  intelligent  man  to  send 
iinto  the  sweats  a  given  number  of  sides  in  nearly  equal  con- 
dition. From  the  entrance  of  the  stock  into  the  reception, 
or  hide  house,  until  it  gets  into  the  sweats,  and,  indeed, 
after  it  has  come  from  the  sweats,  the  object  should  be  to 
equalize  the  sides  in  the  same  pack. 

Especial  attention  to  properly  softening  is  confined  almost 


THE  LEATHER  MANUFACTURE.  19 

exclusively  to  the  dry  flint  stock ;  both  green  and  dry  salted 
hides  soften  without  effort,  and  yet  it  is  important  that  the 
substance  and  condition  should  be  the  same  in  each  pack, 
even  in  this  description  of  hide.  Pickled  hides  should  be 
kept  separate  from  salted,  and  green  salted  from  freshly 
taken  off  hides. 

If  it  is  important  in  sole  leather  hides  to  maintain  uni- 
formity of  condition  in  the  beam  house,  it  is  much  more  so 
in  upper  leather  hides,  kip  and  calfskins.  The  writer  does 
not  hesitate  to  say  that,  in  the  absence  of  this  equality  of 
condition,  upper,  harness  and  calfskins  cannot  be  carried 
through  the  tanning  and  finishing  processes  in  a  workman- 
like manner  and  with  good  results. 

This  difficulty  may  be  aptly  illustrated  by  the  experience 
of  many  small  tanners,  who  cannot  wait  until  they  "  take  in 
enough  stock  "  of  any  one  description  to  make  a  pack  ;  they 
feel  obliged  to  make  up  a  pack  of  hides,  kip  and  calf,  some 
green,  some  fully  dried,  and  some  partially  dried  or  dry 
salted.  The  result  is  that  neither  class  is  well  worked  or 
prepared ;  as  they  had  the  misfortune  of  being  joined  in  the 
beam  house,  they  go  linked  through  the  yard,  and  tho  whole 
pack  comes  out  a  tanner's  abortion. 

But  even  in  cases  where  hides,  kips  and  calfskins  are 
worked  separately  in  the  same  yard,  the  tanner  often  thinks  it 
quite  sufficient  if  he  works  each  class  by  itself,  whereas  there 
are  as  many  conditions  to  be  observed  in  each  class  of  salted 
as  in  dry  hides  ;  not,  perhaps,  in  order  to  secure  a  sound  re- 
sult, but  much  more  is  required  of  this  class  of  stock.  The 
grain  must  be  fully  preserved,  and  the  whole  fiber  must  be  re- 
duced to  a  pulp — as  it  can  be,  when  the  nerve  is  thoroughly 
broken,  and  not  before.  This  nerve  depends  upon  many  con- 
ditions for  its  tenacity.  It  is  easiest  broken  when  fresh  from 
the  animal,  but  may  be  severed  under  any  ordinary  circum- 


20  THE  LEATHER  MANUFACTURE. 

stances.  No  calf,  k>p  or  upper  leather  can  be  made  wltli  those 
yielding  qualities  so  highly  appreciated  in  our  country  without 
the  severance  of  this  nerve*  and  the  sooner  our  tanners  ap- 
preciate this  fact  the  sooner  will  they  make  leather  to  take 
the  place  of  the  French  and  German  calf  ski  as  that  so  largely 
supply  our  best  custom  boot  and  shoe  makers  at  the  present 
time. 

In  all  the  processes,  commencing  with  the  soaking  and  mill- 
ing, or  wheeling,  through  the  lime  and  bate,  each  pelt  must 
be  individuall v  treated,  and  if  the  conditions  are  much  varied, 
more  judgment  and  care  will  be  necessary  in  their  treatment 
as  a  whole  than  if  they  are  substantially  alike. 

In  the  latter  case  ordinary  intelligence  would  suffice  to  per- 
form creditable  work ;  this  degree  of  intelligence  is  all 
that  the  employer  has  a  right  to  expect,  and  hence  the  im- 
portance of  making  as  light  drafts  upon  the  brain-power  of 
his  men  as  possible,  by  making  the  labor  uniform  on  each 
piece  of  stock. 

How  few  calfskin  tanners  in  this  country  think  it  import- 
ant to  classify  their  skins  !  Do  they  not  work  all  skins  from 
six  pounds  to  twelve  in  the  same  pack  ?  Whatever  is  classed 
as  "  veal  "  goes  together  ;  the  first  selection  that  is  thought  of 
is  when  the  finishers  are  wanting  stock  ;  the  packs  are  then 

*  So  little  is  known  in  this  country  of  the  process  of  breaking  the  nerve,  or  even 
of  the  presence  of  such  nerve,  that  I  venture  to  add  this  note,  somewhat  out  of 
the  order  in  which  this  subject  is  treated.  When  a  calf  is  first  killed,  this  nerve 
will  be  seen,  by  close  observation,  twitching  and  contracting  on  the  flesh  for  a  few 
moments  after  death ;  the  whole  flesh  appears  alive  with  muscular  action  ;  when 
closely  observed,  this  action  will  appear  to  be  the  result  of  innumerable  interlacing 
nerves,  which  a  wise  Providence  has  placed  there  to  expand  or  contract  to  meet 
the  requirements  of  the  seasons  and  the  varying  condition  of  the  animal.  When 
these  nerves  become  quiet  and  fixed  they  hold  the  fiber  of  the  skin,  giving  it  a 
compact  and  even  rigid  feeling.  To  demonstrate  the  existence  of  this  nerve,  let 
the  following  experiment  be  tried :  Take  a  green  skin,  throw  it  over  the  tanner's 
beam,  and,  with  a  worker,  put  ten  minutes'  hard  work  on  the  flesh  side  of  one-half 
of  the  skin  ;  the  result  will  be  that  the  half  of  the  skin  worked  will  be  distended 
an;l  soft— even  pulpy.  Much  more  would  this  be  the  effect  if  done  after  soaking 
thoroughly,  as  it  should  be  before  the  usual  beam  work  is  done. 


THE  LEATHEB  MANUFACTURE.  21 

assorted  and  the  tanned  skins  are  selected  out  and  sent  to 
the  currying  shop,  while  the  heavy  ones  are  given  another 
liquor.  This  is  beginning  at  the  wrong  end ;  the  selection 
should  have  taken  place  before  the  skins  entered  the  beam 
house,  when  the  advantages  of  classification  would  have  been 
secured  ah1  the  way  through  the  process.  In  a  well  regulated 
calf  or  kip  skin  yard,  from  the  time  the  skins  enter  the  tan- 
nery they  are  mated  (for  reasons  hereafter  to  be  stated),  and 
continue  this  connection  through  the  whole  after  tanning 
process.  But  how  can  dissimilar  sizes  and  substances  be  suit- 
ably paired,  and  so  placed,  grain  to  grain,  as  to  fully  cover 
each  other? 

What  has  been  said  thus  far  goes  to  the  advantage  of  the 
intrinsic  quality  of  the  stock  ;  but  suppose  some  hides  or  skins 
are  damaged,  or  partially  so  ?  These  should  by  no  means 
be  allowed  to  contaminate  the  good.  They  are  the  sick  mem- 
bers, and  must  be  placed  in  hospital,  under  observation  ;  they 
may  not  all  have  the  same  disease,  and  must  be  placed  in  dif- 
ferent "wards"  or  "apartments"  for  special  treatment. 

"When  one  thinks  of  the  indiscriminate  and  forcing  pro- 
cesses which  valuable  stock  receives  at  the  hands  of  many 
tanners,  the  inhumanity  of  the  treatment  is  forced  on  one's 
mind.  Sick  or  well,  strong  or  weak,  large  or  small,  the  same 
methods,  the  same  trying  ordeal,  must  be  passed  by  all,  and 
that  so  few  should  break  and  fail  is  the  wonder. 

It  re-mains  only  for  me  to  say  a  word  about  the  impolicy  of 
working  a  variety  of  hides  in  the  same  yard.  It  is  not  to  be 
denied  that  some  tanners  succeed  in  making  good  stock  out 
of  a  variety  of  hides  under  treatment  at  the  same  time  ;  but 
this  is  the  exception,  and  should  not  be  ventured  upon  by  the 
average  tnnner.  At  least  one  season's  or  one  year's  hides 
should  be  of  one  kind,  or  as  nearly  so  as  possible.  Buenos 
Ayres,  Montevideo  and  Kio  Grande  are  sufficiently  alike  to 


22  THE  LEATHER  MANUFACTURE. 

be  classed  together  ;  Central  American  and  Matamoras,  and 
even  dry  Texas,  are,  possibly,  similarly  conditioned.  Califor- 
nia and  Western  may  well  be  treated  as  similar  hides,  requir- 
ing like  treatment ;  but  there  cannot  safely  be  treated  dry 
salted  and  dry  flint  hides  in  the  same  beam  house  ;  lime  and 
sweat  stock  cannot  go  through  together  without  danger,  or 
certainly  with  hope  of  the  most  satisfactory  results.  The 
best  leather  is  made  by  tanners  who  work  a  uniform  descrip- 
tion of  hide.  This  is  the  usual  experience,  and  is  based  on 
common  sense. 


CHAPTEE    II. 
PREPARATION  OF  HIDES  FOR  THE  BARK— SWEATING. 

COLD  AND  WARM   SWEATING — CONSTRUCTION    OF   SWEAT  PITS CLEANLINESS, 

LIGHT  AND  IMPENETRABILITY  TO  AIR  NECESSARY  IN  COLD  SWEAT  PITS 

PROPER  CONDITION  OF   STOCK  BEFORE  ENTERING  THE   PITS CARE  NEC- 
ESSARY   IN    THE   SWEATING    PROCESS TREATMENT    AFTER    THE    HIDES 

COME   FROM    THE    PITS PART   LIMING    AND    PART    SWEATING GREASE 

AND  SALT  ON   HIDES. 

In  contradistinction  to  the  sweating  process  of  Southern 
Europe  and  Great  Britain,  the  American  method  is  called 
the  "  cold  sweat  ";  theirs  is  denominated  the  "  warm  sweat." 
In  France,  Germany,  Austria  and  Switzerland,  perhaps  also 
in  other  countries  of  Continental  Europe,  the  tanners  sweat 
their  green  hides  by  piling  one  on  top  of  the  other,  laid 
out  flat,  and  covering  them  up  with  spent  tan  or  horse  ma- 
nure until  decomposition  begins.  This  is  their  process  of  pre- 
paring sole  leather  hides ;  for  upper  they  lime,  substantially  as 
we  lime  our  upper  stock. 

In  this  chapter  both  the  construction  and  practical  opera- 
tion of  the  sweat  pits  will  be  considered.  The  modifications 
and  changes  of  construction  in  the  form  of  sweat  pits  for  tan- 
ners have  kept  pace  with  the  alterations  which  have  been  made 
in  the  building  and  location  of  ice  houses  for  the  people 
at  large.  The  same  principles  govern  both.  A  good  sweat 
pit  would  make  a  good  ice  house  ;  possibly  a  good  ice  house 


2i  THE  LEATHER  MANUFACTURE 

might  not  make  a  good  sweat  pit — but  only  for  the  reason 
that  it  would  not  be  sufficiently  commodious  and  controllable. 

In  Great  Britain  it  is  customary  to  "  steam  sweat  "  sheep- 
skins until  the  wool  yields.  This  is  done  by  inserting  steam 
under  a  false  bottom  of  a  chamber,  hung  up  in  which  are  the 
skins  with  wool  on.  The  two  methods  mentioned  may  be  re- 
garded as  "  warm  sweating  "  in  contrast  with  our  system  of 
"  cold  sweating."  It  may  then  with  truth  be  claimed  that 
our  method  of  sweating  is  peculiar  to  this  country. 

It  is  now  fully  demonstrated  that  a  wood,  brick  or  stono 
structure  on  the  top  of  the  ground  can  be  so  completely  pro- 
tected from  the  rays  of  the  sun  and  other  atmospheric  influ- 
ences as  to  make  a  good  sweat  pit.  The  ice  companies  have 
adopted  surface  structures  of  wood,  "filled  in"  with  saw 
dust,  tan  bark  or  charcoal  between  the  outside  clapboards 
and  the  inside  lining  of  their  buildings,  and  this  same  form 
of  structure  will  make  a  most  serviceable  tanners'  sweat  pit. 
But  since  the  sweat  pit  is  subject  to  greater  changes  of  at- 
mosphere than  the  ice  house,  it  is  desirable  that  the  inner 
lining  of  the  sweat  pit  should  be  of  a  more  enduring  substance 
than  wood.  The  damp  but  warm  atmosphere  of  a  tanner's  sweat 
pit  decomposes  the  fiber  of  the  wood  very  fast — a  sound  hem- 
lock plank  thus  exposed  becoming  worthless  in  a  few  years. 
On  account  of  this  liability  to  decay,  if  for  no  other  reason,  the 
sweat  pits  of  tanners  should  be  constructed  of  stone  or  brick. 
But  these  structures  may  be  wholly  above  ground,  and  should 
be  so  placed  that  a  wheelbarrow  may  be  run  from  the  floor 
of  the  beam  house  into  the  main  passage  way  of  the  sweat 
pit.  These  passage  ways  should  be  wide — not  less  than  six 
to  eight  feet — and  so  thoroughly  lighted,  both  from  top  and 
ends,  as  to  make  the  passage  through  them  by  the  workmen 
both  easy  and  agreeable.  The  hight  of  the  main  passage 
way  should  extend  above  the  surrounding  pits,  and  by  a 


THE  LEATHER  MANUFACTURE.  25 

"  lantern "  construction  of  the  roof  both  light  and  air  can  be 
secured  in  the  passage  ways  below. 

The  pits  themselves  should  extend  from  both  sides  of  the 
main  passage,  and  be  connected  with  folding  doors,  wide 
enough,  when  fully  open,  to  admit  a  wheelbarrow.  Each  of 
these  pits  should  be  large  enough  to  contain  one  pack  of 
hides,  and  high  enough  to  admit  the  hanging  of  a  side 
doubled,  with  a  space  of  fully  two  feet  above  and  one  foot 
below  the  racks,  on  which  or  from  which  the  sides  are  sus- 
pended by  tenter  hooks.  The  width  of  the  pits  should  be 
about  eight  feet.  This  will  give  space  for  two  tiers  of  sides 
and  a  small  passage  to  enable  the  attendant  to  make  his 
examinations.  Both  this  passage  and  the  room  above  and 
below  the  hanging  sides  give  opportunity  to  introduce  light 
and  ventilation  when  required. 

There  is  no  reason  why  these  pits  should  not  be  so  light 
that  close  observations  may  be  made  with  out  the  use  of  a  lamp, 
aud  they  should  always  be  kept  in  such  cleanly  and  orderly 
condition  as  will  permit  the  foreman  or  employer  to  enter 
and  make  inspections  without  fear  of  soiling  their  clothes. 
Too  much  stress  cannot  be  laid  on  this  feature  of  our  more 
modern  sweat  pits.  The  fact  that  such  inspections  are  liable 
to  be  made  at  any  time  keeps  a  most  healthy  check  on  the 
attendant. 

The  temperature  of  the  sweat  pits  should  be  held  under 
control  by  steam  and  cold  water,  with  which  the  main  passage 
should  be  amply  supplied  by  means  of  pipes.  A  properly 
constructed  pit  should  have  a  false  bottom,  under  which  the 
steam  may  be  forced,  to  find  its  way  in  condensed  spray  up 
through  the  suspended  sides.  This  process  will  adequately 
warm  the  pit.  When  too  warm,  cold  water  may  be  thrown 
from  the  mouth  of  a  sprinkler  over  the  whole  surface,  and 
thus,  in  a  few  moments,  cool  the  whole  space,  and  leave  a  de- 


26  THE  LEATHER  MANUFACTURE. 

sirable  moist  atmosphere.  When  in  proper  condition  the 
pits  will  stand  at  a  temperature  of  60°  to  70°,  F.,  with  globules 
of  water  collected  on  all  parts  of  the  suspended  sides,  occa- 
sionally dropping  in  their  condensation  from  the  ends  of  the 
hair. 

Each  one  of  the  pits  should  have  at  least  four  lights,  7  by 
9  inches,  in  the  end,  with  a  lantern  ventilator  in  the  top  of  the 
latter,  which  can  be  opened  and  closed  by  a  cord.  The  pits 
should  be  covered  on  top  by  timbers  flattened  on  three  sides, 
and  heavy  enough  to  hold  up  at  least  two  feet  of  earth.  This 
earth,  sodded  over  and  kept  well  watered,  wih1  amply  protect 
the  pits  from  the  rays  of  the  sun,  and  the  ammonia  which 
arises  from  the  pits  will  produce  a  most  luxurious  growth 
of  grass,  vines  or  flowers,  on  this  earth  covering.  The  sides 
of  the  pits  should  be  protected  by  a  banking  of  earth  or 
spent  tan.  The  former  is  the  most  desirable,  for  this  earth 
may  be  made  the  means  of  cultivating  grape  or  other  vines 
with  the  most  artistic  and  even  serviceable  effect. 

With  pits  thus  constructed  and  under  proper  control,  hides 
may  be  properly  sweat  in  from  three  to  seven  days — usually 
in  about  four  or  five  days.  To  accomplish  this  result  the 
hides  or  sides  must  be  in  proper  condition. 

For  the  most  part  only  dry  flint  hides  are  prepared  by  the 
sweating  process,  in  this  country,  and  yet,  as  we  proceed  in 
our  inquiry,  possibly  we  may  find  that  sweating  in  connec- 
tion with  liming  may  serve  a  most  useful  purpose,  particularly 
for  green  or  dry  salted  foreign  hides.  The  native  green  salted 
hides  are  mainly  taken  by  lime  tanners,  who  find  no  occasion 
to  use  the  sweating  process. 

Flint  dry  hides,  or  indeed  any  hides  that  enter  the  sweat 
pit,  must  first  be  made  absolutely  soft  in  all  their  parts — pates 
as  well  as  skirts  and  butts.  In  this  respect  banners  do  not 
exercise  sufficient  care.  Where  the  hides  are  tender  (liable 


THE   LEATHEK  MANUFACTUKE.  27 

to  break)  there  is  a  strong  temptation  to  stop  short  of  this 
desirable  condition.  Probably  less  breaking  thus  results,  but 
then  "  old  grain  "  and  "  hard  spots  "  will  come  in  to  offset 
the  breaking.  If  at  any  time  half  prepared,  hard  sides, 
should  go  into  the  sweats,  they  should  go  in  with  companions 
equally  delicate  and  tender  in  their  constitution,  and  all 
should  then  be  treated  alike. 

The  sides  should  be  hung  on  the  racks  by  tenter  hooks, 
either  suspended  from  the  shoulder  or  from  the  pate  and 
butt ;  whichever  way  is  adopted,  the  practice  should  be  uni- 
form, so  that  a  uniform  result  may  be  anticipated. 

As  the  sweating  process  advances  with  greater  rapidity 
in  the  top  than  at  the  bottom  of  the  pit,  and  as  the  thicker 
portions  of  the  hide  resist  the  action  of  the  sweat  longer  than 
the  thinner  portions,  it  is  desirable,  as  far  as  practicable,  to 
hang  the  pates  and  butts  higher  than  the  shoulders  and 
bellies,  but  as  this  is  difficult  to  manage,  the  result  is  accom- 
plished by  changing  the  positions  of  the  sides  or  hides  as  they 
advance  in  the  process.  Usually,  after  three  or  four  days, 
the  "  assorting  out  "  and  changing  of  position  commences, 
and  on  the  fidelity  with  which  this  is  done  will  damage  be 
prevented  and  a  good  result  secured. 

No  hides,  however  uniform  in  character,  will  sweat  exactly 
alike,  and  it  is  for  this  reason  that  the  careful  attention  of  the 
employee  must  be  secured.  No  hour  in  the  whole  day  should 
pass  without  a  visit  to  the  advanced  sweats.  When  a  few  sides 
give  indications  of  "  coming  "  prematurely,  before  their  proper 
time,  they  should  be  dropped  to  the  bottom  of  the  pit,  and 
allowed  to  lie  in  piles  until  their  less  advanced  companions 
catch  up  in  the  process  of  decomposition. 

Supposing  all  the%  sides  to  be  in  the  same  state  of  forward- 
ness, the  present  practice  is  to  throw  them  in  the  mill,  and  for 
a  few  moments  wash  out  or  off  the  slime,  and  rub  the  hair  off, 


28  THE  LEATHER  MANUFACTURE. 

or  so  much  of  it  as  can  be  removed  easily.  During  this  short 
and  damaging  process,  two  things  happen :  1.  The  loose 
hair  is  fulled  into  the  flesh  so  firmly  as  to  make  it  difficult  to 
remove  afterward  on  the  beam,  and,  2.  Much  of  the  gelatine 
of  the  hide  is  lost,  as  at  this  period  it  is  in  very  nearly  a  sol- 
uble c  ndition  and  will  part  from  its  proper  lodgment  in  the 
fiber  almost  as  freely  as  the  slime  and  dirt  with  which  the  sur- 
faces are  covered  ;  indeed,  much  of  the  substance  that  is  re- 
garded as  "  slime  "  and  "  dirt  "  is  the  gelatine,  which,  when 
combined  with  tannin,  goes  to  make  leather.  There  is  no 
doubt  that  many  of  even  our  best  tanners  make  too  much 
dependence  on  this  after  milling  to  soften  their  stock,  and 
with  this  end  in  view  allow  the  mills  to  run  on  this  tender 
stock  far  too  long. 

Some  of  our  most  thoughtful  tanners  have  of  late,  to  meet 
this  difficulty,  thrown  the  sides  when  they  first  come  from 
the  pits  into  a  weak  lime  water,  and  allowed  a  slight  reaction 
to  take  place.  This  action  of  the  lime  is  indicated  by  a  slight 
plumping  of  the  side,  and  the  disappearance  of  that  slimy, 
slippery  feel,  which  always  attends  sweat  stock.  Besides 
other  savings,  this  after-liming  prevents,  to  a  great  extent, 
the  hair  from  attaching  itself  to  the  flesh  while  in  the  hide 
mill.  But  beyond  these  savings  I  venture  to  suggest  that  even 
the  slight  liming  here  indulged  in  will  counteract  the  action 
of  the  vitriol  in  the  handlers,  and  to  those  tanners  who  use 
vitriol  this  liming  will  be  of  service,  for  lime  and  vitriot  will 
counteract  and  destroy  each  other.  It  is  well  known  that 
on  purely  lime  stock  vitriol  may  be  used  moderately  with  ad- 
vantage, both  as  a  "  bate"  and  as  a  means  of  plumping  the 
leather. 

It  has  been  demonstrated  that  part  liming  and  part  sweat- 
ing the  same  hides  will  answer  a  very  excellent  purpose. 
The  writer  has  in  his  mind  an  experiment  tried  on  a  large 


THE  LEATHEE  MANUFACTUEE.  29 

scale,  viz.,  on  10,000  Texas  and  New  Orleans  green  salted 
hides,  which  produced  73  pounds  of  leather  to  the  100 
pounds  of  hide,  and  the  leather  thus  made  was  excellent  in 
quality — both  plump  in  offals  and  fine  in  fiber.  If  the  present 
vitriol-raising  process  is  to  be  continued,  and  finds  favor,  in 
my  judgment  this  partial  liming  must  be  resorted  to  if  a 
reasonably  good  buff  is  secured. 

When  we  are  assured,  as  a  justification  of  our  practice,  that 
the  tanners  of  Great  Britain  plump  all  their  bends  and  butts 
with  vitriol,  we  should  remember  that  this  description  of 
leather  is  there  made  for  the  most  part  out  of  green  salted 
hides  from  South  America  or  Spain,  which  are  highly  limed. 
The  English  tanners  occupy  from  eight  to  fourteen  days  in 
their  liming  process.  The  condition  of  the  hide  produced  by 
this  excessive  liming  will  justify  the  use  of  vitriol  without  en- 
dangering the  buff  or  fiber.  With  our  sweat  stock  it  is  far 
different ;  our  sweat  sides  contain  nothing  to  neutralize  this 
mineral  acid,  and  the  result  is  most  disastrous  to  the  buff, 
and  also  to  the  intrinsic  vitality  of  the  fiber. 

There  can  be  no  doubt. that  our  American  system  of  cold 
sweating  is  calculated,  beyond  any  other  known  method,  to 
make  a  firm,  compact  fiber,  when  properly  used,  and,  besides, 
it  is  especially  adapted  to  the  preparation  of  the  dry  hides 
of  our  continent. 

It  only  remains  for  me  to  say  a  word  on  the  subject  of 
"  grease  "  and  "  salt "  as  among  the  hindrances  which  affect 
and  control  the  sweating  of  hides.  All  sweat  tanners  fully 
understand  that  the  salt  (if  the  hide  is  salted  or  pickled) 
must  be  fully  soaked  out  before  the  hide  will  sweat ;  from 
this,  among  other  circumstances,  is  deduced  the  inference  that 
this  process  is  a  decomposing  one — for  so  long  as  the  hide 
is  h  Id  (cured)  by  the  presence  of  salt,  carbolic  acid  and 
other  tawing  ingredients,  the  sweats  will  not  operate  on  it. 


30  THE  LEATHER  MANUFACTURE. 

So,  too,,  if  the  hide  is  covered  with  grease — as  many  of 
our  "Western  and  California  hides  are — it  will  not  sweat 
evenly,  owing  to  the  presence  of  grease  on  some  portions 
more  than  on  others.  If  the  hide  is  covered  all  over  with 
grease,  notwithstanding  the  action  of  the  soaks  and  mills, 
then  this  grease  should  be  removed.  This  may  be  done  by 
an  alkali,  such  as  salsoda,  soda  ash,  potash,  etc.,  of  com- 
merce ;  when  these  cannot  be  obtained,  hard  wood  ashes, 
freely  used  in  the  soaks,  will  turn  the  grease  to  soft  soap, 
and  it  will  readily  wash  off  in  the  mills. 

NOTE. — For  illustration  and  further  description  of  improved  style  of  cold  sweat 
pits,  as  at  present  in  use  by  American  tanners,  see  engravings  in  latter  part  of 
•iris  hook. 


CHAPTER    III 
PREPARATION   OF   HIDES   FOR    THE  BARK— LIMING. 

GETTING  READY  THE  LIMES — THEIR  AGE    AND    STRENGTH EFFECT    OF    THE 

LIME  ON    THE    FIBER — PLUMPING  AND    BATING PROF.  LUFKR;'s  PRO- 
CESS—  THE  "BUFFALO"  METHOD  —  THEIR  RESULTS — HANDLING  IN 

THE   LIMES. 

By  far  the  oldest  method  of  unhairing  the  hide  is  known 
as  the  "  liming  process."  But  old  and  well  established  as 
this  system  is,  there  are  economical  and  wasteful  methods,  both 
in  the  use  of  lime  and  in  working  and  handling  the  hides  by 
this  process  while  in  the  beam  house.  Without  taking  up 
the  time  of  the  reader  by  pointing  out  the  defects,  let  me 
as  briefly  as  possible  call  attention  to  the  most  approved 
methods  of  using  lime  for  the  unhairing  of  hides. 

Lime  for  the  tanner's  use  should  always  be  unslaked,  or  in 
the  "  stone."  When  it  is  supplied  fresh  from  the  kiln,  as  it 
should  be  at  frequent  intervals,  it  should  be  kept  in  a  dry 
and  confined  apartment,  where  neither  moisture  nor  air  can 
reach  it.  This  lime  should  be  "  slaked  "  with  even  more  care 
for  the  tanner  than  is  exercised  by  the  mason  and  finisher. 

The  following  description  indicates  briefly  the  best  method 
of  preparing  the  stone  or  unslaked  lime  for  the  tanner's  use : 
Have  a  half  hogshead  placed  near  the  lime  vat  it  is  proposed 
to  replenish  ;  for  a  pack  of  120  to  140  sides  throw  in,  sajT, 
one  bushel  of  lime ;  dampen  it  by  pouring  on  one  or  two 


32  THE  LEATHER  MANUFACTURE. 

pails  of  water,  and  cover  with  a  thick  canvas ;  a  few  mo- 
ments will  suffice  to  absorb  the  water,  and  considerable  heat 
will  be  produced ;  add  water,  gently,  several  times,  rather 
than  "  drown  "  the  lime  by  an  oversupply  at  any  one  time, 
and  be  sure  and  not  allow  it  to  "  burn  "  for  want  of  water. 
The  hogshead  should  be  kept  covered  until  the  slaking  is 
completed.  When  the  reaction  is  over  the  tub  may  be  filled 
with  water  and  thoroughly  stirred ;  after  settling,  the  liquid 
or  soluble  portion  should  be  poured  off  into  the  vat,  leaving 
all  grit,  dirt  and  unslaked  lumps  in  the  hogshead.  Nothing 
but  pure  lime  water  should  ever  be  allowed  to  go  into  the 
vat ;  this  will  not  only  render  frequent  "  cleaning  out "  un- 
necessary, but  will  save  the  edge  of  the  fleshing  knife,  and 
shorten  the  time  required  in  many  subsequent  operations. 

Some  tanners  prefer  old  and  weak  limes  ;  others  fresh  and 
strong  ones.  Where  old  limes  are  depended  upon,  filled 
with  the  ammonia  of  previous  decomposing  packs,  the  writer 
would  suggest  that  damage  may  result  unless  care  is  observed, 
for  this  use  of  old  limes  involves  in  a  measure  the  principle 
of  the  sweating  process.  This  method,  on  the  whole,  may 
be  regarded  as  only  suitable  to  cold  weather;  in  warm 
weather  it  certainly  is  too  dangerous  for  general  adoption. 

All  tanners  will,  however,  recognize  the  importance  of 
making  a  difference  between  the  process  for  upper,  calf,  kip, 
harness  and  belting  leather,  and  that  for  sole  leather. 

For  the  former  kind  of  stock  not  less  than  three  or  four 
days  should  be  consumed  in  the  process  ;  this  length  of  time 
will  kill  the  grease,  and  fairly  plump  (distend)  the  fiber.  The 
effect  of  the  after  process  of  bating  is  to  leave  the  tissues  of 
the  hide  relaxed  and  the  fiber  elongated — just  the  condition 
in  which  the  fiber  should  be  left  in  order  to  make  tough, 
flexible  leather,  for  when  once  the  fiber  of  the  hide  has  been 
unduly  expanded,  and  the  gelatine  cells  broken  or  disturbed, 


THE  LEATHER  MANUFACTURE.  33 

they  can  never  again  be  brought  back  to  the  closed  and  com- 
pact condition  in  which  they  were  found  in  the  natural  hide. 
A  microscopic  examination  of  the  condition  of  the  fiber  of 
tanned  leather  will  leave  no  doubt  as  to  the  process  which 
has  been  pursued  in  the  beam  house.  It  is  possible  so  to 
"starve"  the  leather  in  the  handlers  and  the  after  process 
by  weak  decoctions  as  to  break  down  the  distinct  membra- 
nous cells  which  hole],  the  gelatine,  but  usually  this  is  done 
in  the  beam  house.  If,  added  to  the  swelling  and  depleting 
process  in  the  beam  house,  a  starving  process  is  followed  up 
in  the  handlers  or  the  layaways,  then,  instead  of  plump,  well- 
filled  leather,  we  shall  notice  a  stringy,  elongated  fiber,  consist- 
ing for  the  most  part  of  animal  tissues,  and,  as  these  do  not 
absorb  tannin  to  the  same  extent  that  gelatine  does,  of  course 
we  have  no  gain,  and  have,  externally,  a  coarse,  broken  offal 
nnd  grain.  Indeed,  we  reproduce  the  examples  which  we  see 
daily  coming  in  from  small  country  yards.  The  waste  which 
this  process  induces  will  surely  prevent  tanners  who,  make 
such  leather  from  reaping  large  profits  or  from  competing 
with  those  who  make  the  most  possible  out  oi  the  stock 
which  is  placed  in  their  hands  to  treat, 

Three  or  four  days  in  the  lime  w411  not  improperly  fill  the 
hide,  and  when  unhaired  it  may  be  speedily  reduced  to  a 
natural  condition.  This  reduction  (depletion)  will  be  well 
begun  by  throwing  the  hides,,  or  sides,  into  a  wheel,  and,  with 
a  flow  of  warm  water  turned  on,  running  for  ten  minutes. 
The  advantage  of  warm  instead  of  cold  water  is  very  marked, 
and  warm  water  may,  at  this  stage  of  the  process,  be  freely 
used  with  safety.  It  is  always  safe,  on  hides  filled  with  lime, 
to  use  heat  to,  the  extent  of  100°  F,,  or  as  hot  as  can  be  borne 
by  thrusting  in  the  hand  and  wrist.  This  rinsing  process  will 
ijomove  the  greater  portion  of  the  lime,  and  will  ordinarily 
prepare  the  hides  for  the  liquor;  but  some  tanners  are  so  ., 

3  ' 


S-A  THE   LEATHER   MANUFACTURE. 

particular  as  to  insist  on  bating  still  more  by  the  use  of  hen 
manure,  or  some  "sour,"  such  as  may  be  prepared  with 
wheat  bran  or  molasses. 

For  sole  leather  this  latter  precaution  is  quite  unnecessary ; 
but  for  fair  or  harness  leather,  and  perhaps  for  calf  and  kip, 
where  not  only  a  clean  but  a  soft  grain  is  demanded,  such 
extra  bating  may  be  justified. 

Up  to  this  time  the  treatment  of  full  grown  hides  only  has 
been  considered,  where  they  have  been  handled  with  lime  for 
three  or  four  days.  If  filled  with  lime,  by  being  retained  in 
the  process  for  six  or  eight  days,  more  care  and  more  par- 
ticular treatment  in  the  bate  may  be  necessary.  But  the 
writer  would  leave  all  such  tanners  to  work  out  their  salvation 
as  best  they  may.  This  is  certainly  true,  that,  as  a  rule,  for 
all  upper  stock,  the  hides  or  skins  should  go  into  the  handlers 
as  free  as  possible  from  lime,  while  sole  leather  stock  may  be 
trusted  to  right  itself  as  it  passes  through  the  sour  liquors  of 
the  handlers,  provided  the  fiber  has  not  been  unduly  strained 
(expanded)  in  the  beam  house. 

Thus  far  the  well-known  and  generally-used  methods  of 
unhairing  by  lime  have  been  considered,  but  there  are  other 
forms  in  which  lime  performs  a  more  or  less  conspicuous 
part.  Eeferring,  in  the  first  instance,  to  Prof.  Lufkin's  pro- 
cess, the  writer  is  enabled  to  state  with  great  particularity  its 
details,  through  the  kindness  of  Mr.  Charles  Cooper,  of  Spar- 
rowbush,  N.  Y.,  than  whom  no  man  has  had  greater  experi- 
ence in  its  use.  He  has  prepared,  for  several  years  in  suc- 
cession, not  less  than  50,000  hides  by  this  process,  and  with 
great  success,  as  the  superior  leather  he  has  produced  will 
attest.  His  packs  were  made  up  of  about  50  hides  each, 
either  cured,  green  salted,  or  dry  Buenos  Ayres  or  Rio 
Grande.  The  green  hides  weighed  50  and  the  dry  20  pounds 
each.  For  such  a  pack  he  would  slake  80  pounds  of  stone 


THE   LEATHER  MANUFACTURE.  35 

lime,  in  the  manner  already  indicated,  except  that  the  lime  is 
not  watered  after  the  slaking  process  has  been  finished 
This  leaves  the  lime  of  the  consistency  of  a  thick  paste. 
While  in  this  state  take  a  small  portion  and  knead  thorough- 
ly with  10  pounds  each  of  soda  ash  and  pulverized  sulphur  ; 
when  these  three  products  are  well  mixed,  and  while  the  lime 
is  yet  ivarm,  turn  the  whole  in  together  and  mix  thoroughly ; 
after  doing  this  take  lime  liquor  from  the  vat  and  fill  the  cask, 
stirring  all  the  while ;  when  completed  pour  into  the  vat  and 
thoroughly  plunge  the  whole.  No  more  liquor  should  be  in 
the  vats  than  sufficient  to  cover  the  100  sides  when  thrown 
in.  It  is  desirable  to  keep  the  lime  thus  made  up  to  summer 
heat  by  the  use  of  steam,  which  may  be  done  by  inserting  a 
steam  pipe  while  the  pack  is  raised.  The  handling  should 
be  performed  once  or  twice  each  day  if  the  hides  are  thrown 
into  the  vat  in  the  usual  way ;  but  if  handled  on  sticks  or 
reeled,  then  plunging  and  more  frequent  handling  will  facili- 
tate the  operation. 

As  to  the  advantages  of  this  process,  the  writer  would  say 
that  the  sulphur  modifies  the  harshness  of  the  lime  and  soda 
ash,  and  renders  them  almost  as  controllable  in  the  hide  as 
soft  soap,  for,  while  the  hide  may  remain  in  the  lime  for  an 
equal  length  of  time  as  with  the  old  process,  there  is  not,  the 
same  swelling,  nor  the  same  harshness,  and  a  few  minutes 
of  wheeling  in  warm  water  will  reduce  the  pelt  to  almost  the 
consistency  obtained  in  sweat  stock.  There  is  no  question 
that  it  is  a  good  method  of  unhairing  for  all  kinds  of  hides  or 
skins,  and  when  a  soft  and  smooth  grain  is  desirable  it  is  a 
valuable  improvement.  Of  course,  it  is  slightly  more  expen- 
sive than  pure  lime,  and  for  this  reason  has  not  found  general 
favor. 

The  next  innovation  upon  the  old  system  of  liming  may 
be  called,  for  the  sake  of  distinction,  the  "Buffalo"  method. 


86  THE  LEATHER  MANUFACTUBE. 

This  method  depends  largely  upon  warm,  or  even  hot  water, 
to  complete  the  process.  The  hide  is  prepared  in  the  usual 
way,  and  is  then  thrown  into  a  strong  lime  for  eight  to  ten 
hours,  when  it  is  taken  out  and  immersed  in  water  heated  up 
to  110°  F.  The  warm  water  soaks,  softens  and  swells  the 
roots  of  the  hair,  and  very  much  such  a  result  is  obtained  as 
in  "  scalding"  hogs.  So  little  lime  really  permeates  the  inner 
fiber  that,  after  a  slight  wheeling,  the  sides  may  be  thrown 
into  cold  water  and  allowed  to  cool  and  plump,  preparatory  to 
taking  their  places  in  the  handlers.  The  process  is  strongly 
commended  for  sole  leather,  particularly  where  great  firm- 
ness of  fiber  is  desired.  The  tanner  who  tries  it  must  be 
satisfied  if  he  gets  twenty  to  thirty  sides  per  man  unhaired 
and  fully  ready  for  the  liquor,  per  day. 

Besides  these,  we  have  many  patented  methods,  both  for 
softening  and  unhairing,  but  as  they  are  all  founded  upon 
supposed  secrets,  and  have  some  powerful  alkali  as  their 
base,  the  writer  will  not  at  present  indicate  their  merits. 
It  will  be  sufficient  to  say  that,  up  to  this  time,  they  have 
made  no  material  progress. 

It  now  only  remains  to  describe  some  of  the  methods  of 
handling  while  in  the  process  of  liming.  The  old  method  is 
to  "throw  in"  and  "haul  up"  from  an  ordinary  vat — 6  feet 
wide  by  8  or  9  feet  long.  This  is  so  laborious  that  the  sides 
or  hides  frequently  do  not  get  hauled  more  than  once  each 
twenty-four  hours.  Among  the  labor-saving  methods  in  this 
department  the  following  may  be  mentioned : 

1.  "  String "   the    sides    or    hides  by  tying  pates   and 
shanks  together  and  reel  over  from  one  vat  to  another.    [The 
reel  recommended  in   Chapter  VII.,  on    "Handling,"   and 
which  is  illustrated  on  a  subsequent  page,  will  also  answer 
for  this  purpose.] 

2.  Hang  on  poles  or  sticks  by  throwing  the  hides  or  sides 


THE   LEATHER  MANUFACTURE.  37 

over,  resting  on  the  shoulder — butt  and  pate  down.  The  lime 
liquor  is  plunged  and  thus  a  most  perfect  agitation  and 
handling  is  effected. 

3.  Have  the  lime  vats  sixteen  feet  long ;  place  the  pack, 
while  yet  in  whole  hides,  in  one  end,  resting  on  each  other  ; 
each  hind  shank  should  be  fastened  to  a  rope  or  strong  string 
five  feet  long,  with  a  noose  at  its  end,  which  should  be 
dropped  over  an  iron  upright  at  the  corner  of  the  vat.  If 
this  noose  is  no  larger  than  the  iron  stanchion,  of  course  the 
top  noose  will  indicate  and  draw  the  top  hide.  One  man  on 
each  side  of  the  vat  will,  by  the  use  and  guide  of  these 
strings,  transfer  the  pack  of  hides  from  one  end  to  the  other 
of  the  vat  in  a  few  minutes.  This  system  will  always  leave 
one  end  of  the  vat  unoccupied,  and  while  thus  situated  it  may 
be  "heated  up,"  "plunged"  or  "strengthened." 

There  is  an  advantage  in  connection  with  the  latter  sys- 
tem which  cannot  be  too  strongly  urged  upon  tanners.  It 
enables  them  to  lime  their  hides  whole,  and  to  split  them  af- 
ter the  liming  process  is  complete,  and  this  in  turn  makes 
straight  lines.  For  belt  or  harness  leather  tanners  this  is 
very  important.  All  hides  that  are  split  before  being  limed 
will  be  crooked  and  irregular  on  the  "  back  line,"  for  the  rea- 
son that  lime  takes  hold  on  (contracts)  more  the  thin  than 
the  thick  portions  where  the  whole  hide  is  equally  exposed. 
The  consequence  is  that  the  shoulders  contract  more  than 
the  Lutts.  This  leads  to  waste  where  long  straight  lines  are 
neecWl  in  the  catting,  as  with  belting  and  harness  leather. 


CHAPTEE   IV. 

PKEPAKATION  OF  HIDES  FOE  THE  BAEK— FLESHING 
AND  TEIMMINQ. 

THE  BEAM  WORK CLOSE  FLESHING,  WITHOUT   BREAKING   THE   GLUE  CELLS 

FLESHING   LIME   SLAUGHTER   STOCK WORK   TO    BE    DONE    BEFORE 

LIMING FLESHING    SWEAT     STOCK IT    SHOULD     BE    DONE    WITH    A 

WORKER THE    GERMAN    FLESHER TRIMMING CROP    LEATHER   AND 

BACKS ADVANTAGES     OF    TRIMMING     UPPER     AS     WELL     AS     SOLE 

"  ROUNDING  " TRIMMING      BEFORE     TANNING BEST      METHOD       OF 

UTILIZING    THE    HEAD,    PATE,    ETC. 

By  far  too  little  attention  is  paid  to  beam  work  by  Ameri- 
can tanners.  No  amount  of  labor  or  care  in  the  after  process 
can  atone  for  neglect  in  this  department.  The  flesh  should 
all  be  removed,  and  the  natural  structure  of  the  hide  should 
not  be  disturbed  or  even  touched  with  the  edge  of  the  flesher. 
The  difficulty  of  accomplishing  this  with  the  careless,  unap- 
preciated and  unrequited  labor  at  present  employed  in  this 
service,  is  great ;  but  when  tanners  come  to  understand  that 
both  national  and  international  tastes  and  wants  demand 
that  this  work  be  properly  performed,  there  will  be  no  diffi- 
culty in  securing  the  necessary  reform.  It  is  estimated  that 
the  additional  fleshing  will  cost,  in  labor,  three  cents  per  side 
with  lime  stock  and  two  cents  per  side  for  sweat  stock,  while 
it  will  deprive  the  side  of  about  one-half  a  pound  of  fleshy, 
fibrous  matter,  when  tanned.  This,  then,  is  the  sacrifice 
tanners  are  required  to  make  in  order  to  meet  the  foreign 


THE   LEATHER  MANUFACTURE.  39 

demand  and  taste,  as  well  as  give  better  satisfaction  to  con- 
sumers at  home. 

If  the  question  was  between  removing  the  flesh  and  cut- 
ting the  cells  that  contain  the  gelatine  on  the  one  hand,  or 
leaving  all  the  flesh  on  and  retaining  the  structure  of  the 
hide  intact,  tanners  should  of  course  prefer  the  latter ;  but 
there  is  no  such  alternative.  The  flesh  may  be  removed  with- 
out injury  to  the  structure  of  the  hide,  and  this  should  be 
done  by  all  tanners  who  pretend  to  commendable  workman- 
ship. A  clean  flesh  is  desired  not  more  by  our  own  manufac- 
turers than  it  is  demanded  by  those  of  Europe,  and  both 
should  be  gratified.  If  persistent  and  dogmatic  statement 
will  accomplish  reform  in  this  important  department  of  the 
tanner's  art,  the  writer  proposes  to  use  both  in  the  way  of 
entreaty  and  admonition. 

The  fleshing  of  "  lime  slaughter  stock  "  and  of  "  dry  hide 
sweat  stock"  are  quite  different  operations,  and  must  be  con- 
sidered separately. 

Our  practice  in  regard  to  the  first  class  is  to  throw  the 
hides  into  the  soaks  for  a  day  or  two — just  long  enough  to 
cleanse  all  the  blood,  salt  and  other  impurities  from  them — 
then  draw  from  the  soaks  and  split,  and  throw,  into  the  lime, 
paying  no  attention  to  the  flesh  until  they  come  on  the  beam, 
after  passing  through  the  lime.  The  hide  is  plumped  by  the 
action  of  the  lime,  and  the  theory  is  that,  when  the  flesh  is 
thus  swollen  and  raised,  it  may  be  removed  with  less  danger 
than  if  done  before  the  hide  was  plumped.  This  is  undoubt- 
edly true,  if  only  the  same  labor  and  skill  is  to  be  employed 
in  each  case.  But,  on  the  theory  of  accomplishing  fully  what 
we  concede  to  be  desirable,  the  "meat"  must  be  removed 
from  the  flesh  before  the  hides  go  into  the  lime,  and  the  meat 
should  be  "  worked  off,"  and  not  "  cut  off."  The  "  cutting 
off  "  implies  skilled  labor,  but  the  "  working  off"  is  more 


40  TfiE  LEATHER  MANUFACTURE, 

economically  done  by  willing,  unskilled  labor*  When  the 
meat  on  the  hide  ('which  should  have  been  left  on  the  carcass) 
has  been  removed;  two  things  will  be  accomplished :  1st.  The 
action  of  the  worker  will  have,  to  some  extent,  broken  (dis- 
tended) the  ilerve  of  the  hide  ,'  and,  2d.  All  obstruction  to  the 
uniform  liming  of  the  hide  will  be  removed,  for  patches  of 
meat  on  the  flesh  side  obstruct  the  action  of  the  lime,  as  all 
good  tanners  concede. 

When  it  becomes  fully  understood  among  tanners  that 
all  tbe  flesh  from  slaughter  limed  stock  must  be  removed 
not  only  in  the  beam  house,  but  while  the  hides  are  whole 
and  before  they  go  into  the  lime,  it  is  not  unreasonable  to 
suppose  that  some  mechanical  contrivance  will  be  devised  to 
accomplish  the  work.  At  present  we  are  compelled  to  over- 
come this  obstacle  by  manual  labor,  and  hard,  disagreeable 
work  it  is.  But  the  actual  money  cost  is  not  more  than  six 
cents  per  hide,  and  as  this  labor,  thoroughly  performed,  will 
render  the  after  beam  work  much  easier,  the  writer  ventures 
to  say  that  no  tanner  making  this  stock  can  long  resist  the. 
innovation.  Many  of  our  upper  and  harness  leather  tanners 
do  at  present  remove  the  meat  before  liming,  but  the  practice 
is  not  general.  In  another  chapter  the  reason  for  liming  the 
hide  whole  has  been  explained,  and  that  subject  need  not 
here  be  entered  into. 

The  fleshing  of  sweat  stock  is  quits  different  from  that 
necessary  where  lime  is  used.  The  beam  hand  is  always  cut- 
ting or  working  on  a  soft,  pulpy  substance,  and  should  never 
use  the  edge  of  the  flesher  except  to  trim  the  edges  or  cut 
the  filmy  portions  attaching  to  the  flesh.  All  extraneous  flesh 
and  hair  may  be  readily  worked  off  from  sweat  stock  for  the 
price  already  indicated,  by  a  fine  tooth  worker;  but  these 
teeth,  if  long  and  sharp,  are  likely  to  cut  the  outer  cells  of 
the  fiber.  It  would  be  better  to  remove  the  flesh  with  a 


THE   LEATHER  MANUFACTURE.  41 

Smooth-edged  worker,  which  may  be  done  at  a  cost  not  to 
exceed  two  cents  per  side.  The  saving  in  the  amount  of  flesh 
and  tissue  removed,  and  the  damage  avoided  from  the  cutting 
of  the  fiber,  will  amply  repay  the  extra  cost.  There  are  two 
machines,  either  now  offering  on  the  market  or  soon  to  be 
introduced,  one  of  which  proposes  to  remove  the  flesh  while 
in  the  beam  house — the  power  beam  worker,  of  Mr.  Lampert,  of 
Rochester,  N.  Y.— and  the  other  is  intended  to  shave  or  cut 
the  flesh  off  after  it  is  tanned — the  new  buffing  and  whitening 
machine,  introduced  by  Mr.  Caller,  of  Salem,  Mass.  But 
until  one  or  both  of  these  machines  have  demonstrated  the 
success  which  is  claimed  for  them  tanners  had  better  work 
off  the  flesh,  as  already  indicated. 

The  usual  flesher  and  half  round  beam  are  too  familiar  to 
the  tanner  to  require  notice  in  this  connection,  but  within  a 
few  years  the  French  and  German  beam  knife  has  been  in- 
troduced into  this  country  and  received  with  general  favor. 
This  knife  is  about  one-third  longer  than  ours,  and  is  not 
more  than  two  inches  wide ;  the  material  is  the  best  steel, 
and  the  knife  is  not  more  than  a  quarter  of  an  inch  in  thick- 
ness on  the  rib  or  center.  The  blade  is  so  supple  that  the 
handles  can  almost  be  brought  together.  It  is  claimed  for 
this  knife  that,  by  bending  round  the  convex  form  of  the 
beam,  it  makes  a  flatter  cut  on  the  flesh  of  the  side,  less  con- 
cave than  a  stiff,  straight-edged  flesher  cutting  on  an  oval  or 
convex  surface.  To  this  extent  the  new  knife  certainly  does 
present  advantages,  and  may  be  safely  trusted  to  do  good 
work  in  skillful  hands. 

In  the  year  1838,  a  tanner  in  the  State  of  New  York,  in 
obedience  to  the  suggestion  and  order  of  a  manufacturer  of 
boots  and  shoes,  commenced  to  "  crop "  his  sole  leather. 
The  full  extent  of  the  demand  at  first  was  100  sides  per  week. 
This  demand  grew,  as  other  manufacturers  came  to  see  the 


42  THE  LEATHER  MANUFACTURE. 

economy  of  the  practice,  until  2,000  sides  per  week -were  re- 
quired in  1844.  And  now,  in  1876,  probably  not  less  than 
1,000,000  sides  of  "  union  crop  and  backs  "  are  manufactured 
yearly  in  the  United  States,  and  sold  both  in  this  country 
and  Europe.  Within  a  year  or  two  the  "  crop  "  form  of 
trimming  has  largely  given  way  to  the  "back"  form.  The 
latter  differs  from  the  former  only  in  the  removal  of  the  pate, 
at  the  point  where  the  throat  is  usually  cut,  which  makes  the 
shape  of  the  side  more  compact,  and  in  harmony  with  the 
"  bend  "  leather  of  Great  Britain.  There  must  be  some  ad- 
vantages in  this  method  of  trimming,  or  otherwise  the  trade 
would  not  have  grown  so  rapidly,  and,  to  acknowledge  this, 
is  to  concede  that  still  other  improvements  may  be  made. 
Let  us  inquire  what  they  are. 

The  tanners  of  Great  Britain,  who  certainly  study  the 
economies  of  their  trade  more  thoroughly  than  the  same 
class  in  any  other  country,  not  only  trim  the  bellies,  but  also 
the  shoulders,  from  their  butts  and  bends.  The  following 
reasons  may  be  assigned  for  their  practice  : 

1st.  The  shoulders  and  offal  are  much  thinner  than  the 
butts,  and  therefore  tan  in  shorter  time. 

2d.  The  offal  being  used  where  a  tough  fiber  is  required, 
slack,  or,  at  most,  a  full  tannage  is  all  that  is  required. 

3d.  The  boot  and  shoe  manufacturers,  not  only  of  Europe 
but  of  America,  have  so  classified  their  work  that  those 
who  use  butt  leather  largely  do  not  require  so  much  "  inner 
soling"  and  "  welting  "  as  would  come  from  the  bellies  and 
shoulders  of  the  hides  which  would  give  them  just  the  de- 
scription of  sole  leather  required. 

But  the  upper  leather  tanners  of  Great  Britain  also  trim 
(round)  their  upper  leather,  notably  so  their  East  India  kips. 
The  good  sense  displayed  in  this  process  should  be  adopted 
by  the  tanners  in  this  country,  particularly  on  all  East  India, 


THE  LEATHER  MANUFACTURE.  43 

Hussian  or  native  murrain  kips.  The  bellies  and  shoulders 
of  these,  when  finished  on  the  grain,  make  a  most  ser- 
viceable leather  for  women's  and  children's  shoes,  while  the 
butts,  finished  on  the  flesh,  answer  for  a  stout  boot  or  shoe. 
This  method  of  rounding  light  upper  sides  and  kips  recalls 
the  economy  of  our  fathers,  when  it  was  customary  to  make 
" magpie"  leather — that  is,  grain  and  wax  finished  on  the 
same  piece.  The  farmer  had  his  single  hide,  taken  off  in  the 
fall,  tanned  by  the  halves,  and  finished  "  magpie."  This  gave 
him  the  thin  bellies  and  offal,  grain  blacked  for  women's  and 
children's  shoes,  and  the  thicker  portions,  "  waxed,"  for  wear 
by  himself  and  older  sons.  One  of  these  days  we  shall  imi- 
tate the  economy  of  our  fathers,  and  treat  the  whole  shoe 
and  leather  consuming  people  as  one  family,  whom  it  is  our 
duty  to  supply  with  leather  fabrics  upon  the  most  economic 
plan,  and  when  this  time  arrives  we  shall  find  ourselves  imi- 
tating very  closely  the  habits  and  practices  of  the  leather 
and  shoe  manufacturers  of  Great  Britain,  for  they  are,  no 
doubt,  far  in  advance  of  us  in  all  these  respects.  It  is  prob- 
ably true  that  the  population  of  Great  Britain  is  better  and 
more  economically  shod  than  any  people  in  the  world.  A 
portion  of  the  economy  is  due,  however,  to  iron  rather  than 
leather.  Much  of  the  economy  here  conceded  arises  from 
their  method  of  trimming  and  rounding  their  hides  and  skins. 
That  which  belongs  to  the  glue  maker  never  goes  beyond  the 
beam  house  in  any  tannery  in  Europe,  and  this  includes  the 
hide  from  the  pates,  heads,  shanks  and  tails.  In  treating  of 
the  "  savings  of  the  tan  yard "  their  methods  of  utilizing 
these  as  well  as  the  hair  and  other  serviceable  offal  will  be 
explained. 

Our  best  city  custom  harness  makers  can  scarcely  real- 
ize the  fact  that,  until  within  a  few  years,  they  have  been 
compelled  to  buy  the  offal  of  all  the  sides  they  cut.  Now 


44  THE   LEATHER   MANUFACTURE. 

they  buy  only  the  backs,  or  just  such  portions  as  they  need, 
while  the  trunk,  collar  and  strap  leather  manufacturers  can 
get  their  supply  from  the  bellies  of  these  sides.  This  eco- 
nomical arrangement  we  borrow  from  Great  Britain. 

There  is  one  advance,  however,  in  the  economies  of  leather 
trimming  and  cutting  which  owes  its  origin  to  Lynn,  Mass., 
viz.,  the  cutting  of  soles,  and  sorting  them  to  suit  each  spe- 
cial manutacture.  This  gives  each  what  he  requires,  and 
only  that.  Upper  and  calf  fronts  are  furnished  in  a  similar 
way  to  manufacturers  in  all  Southern  Europe,  but,  so  far  as 
the  writer  has  observed,  the  practice  of  furnishing  soles  to 
large  manufacturers  is  confined  to  this  country. 

The  trimming  of  hides  used  for  belts,  bags,  and  more  re- 
cently for  enameled  leather  for  carriages  and  furniture  cov- 
ering, should  by  this  time  be  familiar  to  all.  The  practice, 
however,  marks  an  advance  in  the  progress  of  the  art  which 
gives  promise  of  infinite  extension  and  profit. 

In  closing  this  chapter  the  writer  wishes  to  offer  a  sugges- 
tion. The  head  of  the  ox  or  the  cow  is  now  skinned  while 
yet  attached  to  the  body,  and,  as  it  is  done  by  the  usual 
skinner,  who  comprehends  that  the  hide  is  more  valuable  by 
the  pound  than  the  coarse  meat,  he  leaves  as  much  of  the 
meat  as  possible  on  the  skin  rather  than  the  head,  and  this 
policy  will  probably  continue  until  the  head  is  severed  from 
the  body  while  the  skin  remains  on,  and  is  in  this  condition 
handed  over  to  men  or  women  whose  special  training  will 
induce  them  to  skin  the  cheeks  and  throat  together  in  one 
piece,  leaving  the  "pate"  proper  to  be  skinned  and  wholly 
handed  over  to  the  glue  maker.  If  this  is  carefully  done, 
the  skin  of  the  cheeks  and  throat  will  give  four  or  five  feet 
of  fine  grain  leather,  besides  two  or  three  pounds  of  glue 
stock,  for  this  head  piece  should  be  split  while  in  the  lime, 
and  only  the  grain  sent  into  the  yard  to  tan,  while  the  split 


THE  LEATHER  MANUFACTURE.  45 

portion  should  go  for  glue.  The  nose  and  lips  should  be  cut 
off  while  fresh,  and  handed  over  to  the  sausage  makers,  who  so 
well  understand  how  to  scald,  pickle  and  prepare  these  deli- 
cate morsels  for  human  food.  The  meat  should  be  carefully 
cut  from  the  head  while  fresh,  and  made  into  sausages.  The 
bone,  including  the  pith  of  the  horn,  should  be  crushed  or 
ground  into  a  fertilizer,  and  the  horns  handed  over  to  the 
button  or  comb  maker. 

Many  of  these  processes  are  now  adopted  in  the  final  dis- 
position, but  all  are  retarded,  and  the  result  injured,  by  the 
mistake  of  skinning  the  hide  from  the  head  while  attached  to 
the  carcass.  Let  the  tanners  consent  or  insist  on  this  sepa- 
ration of  the  head  when  they  buy  their  hides,  and  we  may 
depend  upon  immediately  taking  one  step  forward  in  the  di- 
rection of  a  more  economical  method. 


CHAPTEE    V. 
GEINDING  BAEK— BAKK  MILLS. 

THE  INEXPENSIVE  AND    ABUNDANT    POWER   OF    SOLE   LEATHER  TANNERIES 

GRINDING   BARK   FINE  AND  UNIFORM USEFULNESS  OF  SCREENING   THE 

GROUND      BARK THE    DOUBLE-GRINDING     MILL ITS     EFFECTIVENESS 

WITH  DAMP  BARK THE  ALLENTOWN   MILL ADVANTAGE  OF  A  STRONG 

MILL  AND  WEAK  COUPLER THE  SAW  CUTTING  MILL A  BARK  CRUSH- 
ING MACHINE — THE  PROPER  SPEED  AT  WHICH  MILLS  SHOULD  BE  RUN 
TANNIN  LEFT  IN  THE  BARK. 

It  will  be  conceded  by  all  practical  tanners  that  the  prep- 
aration and  proper  grinding  and  leaching  of  bark  stands  at 
the  head  of  all  the  economies  of  the  tanner's  art.  The  very 
large  number  of  imaginary  and  real  improvements  made  in 
this  department  are  so  many  concessions  to  the  importance 
which  is  attached  to  it  by  tanners  and  inventors.  Patents 
almost  without  number  have  been  obtained  on  bark  mills  and 
their  attachments,  and  on  learvhes  and  their  various  methods 
of  heating  and  handling.  Life  is  too  short  and  space  too 
limited  to  review  all  these  improvements  and  patent  claims. 
It  will  be  sufficient  for  the  present  purpose  to  indicate  the 
methods  and  processes  which  have  gained  the  most  general 
adoption  in  our  largest  and  best  constructed  tanneries. 

The  successful  burning  of  wet  spent  tan  in  detached  fur- 
naces has,  more  than  any  one  or  all  causes  combined,  con- 


THE  LEATHER  MANUFACTURE.  47 

tributed  to  a  reform  in  the  grinding  and  leaching  of  bark. 
Whether  to  furnish  the  motive  power  to  grind  the  bark,  or 
the  heat  to  extract  the  strength,  wet  spent  tan  has  afforded 
a  substitute  for  water  power  and  wood  or  coal  fuel,  and  has 
proved  so  complete  a  substitute  that  all  previous  expedients 
have  been  abandoned.  So  absolutely  inexpensive  is  this 
material  that  power  and  heat  may  be  used  without  stint  or 
limit  in  the*  manipulations  of  all  our  modern  sole  leather 
tanneries.  "  Sole  "  leather  tanneries  are  particularized  be- 
cause upper  leather  tanners  usually  are  in  short  supply  of 
refuse  tan  to  do  all  this  work,  and  they  even  now  find  it  prof- 
itable to  dry  or  partially  dry  their  tan,  with  ah1  the  improve- 
ments for  burning  wet  spent  tan  open  to  their  use,  thus  prov- 
ing that  "  water  "  does  not  increase  the  heat-giving  proper- 
ties of  tan,  but  diminishes  them,  notwithstanding  the  learned 
opinions  of  experts  to  the  contrary. 

The  fact  then  stands  conceded  that  the  wet  spent  tan  from 
an  ordinary  sole  leather  tannery  will  give  ample  power  to 
grind  all  the  bark  and  heat  all  the  liquor  required.  If  any 
further  saving  of  labor  can  be  suggested  by  the  use  of  more 
power  and  more  heat,  they  can  readily  be  obtained  by  the 
surplus  tan  now  thrown  away.  Therefore  we  go  into  the 
economic  consideration  of  this  question  with  an  absolute  me- 
chanical power  without  limit.  The  tanner  may  grind  to  any 
degree  of  fineness  ;  he  may  screen  and  return  to  the  mill  any 
portion  of  his  bark  ;  he  may  convey  up  or  down,  or  laterally, 
to  any  required  distance,  either  his  dry  or  spent  tan.  '"With 
such  power,  if  he  fail  to  extract  the  whole  strength,  and  do 
it  in  the  most  acceptable  and  satisfactory  manner,  he  has  no 
one  to  blame  but  himself. 

The  importance  of  grinding  bark  fine,  and  yet  uniformly 
so,  without  dust  on  the  one  hand  or  large  coarse  lumps  on 
the  other,  is  conceded  to  be  very  great.  Dust  obstructs,  and 


48  THE  LEATHER  MANUFACTURE. 

coarse  lumps  prolong  the  process  of  leaching.  Imperfect 
grinding  does  more :  it  necessitates  the  use  of  extreme  heat 
to  extract,  whereas  if  the  bark  is  uniformly  and  properly 
ground  very  little  artificial  heat  will  suffice  in  winter,  and  no 
more  heat  than  that  of  water  at  the  ordinary  temperature 
will  be  required  to  extract  the  tannin  in  summer. 

For  more  than  forty  years  tanners  have  been  seeking  the 
best  bark  mill.  In  this  respect  they  are  lik^  the  farmers 
who  seek  the  best  plow.  Both  bark  mills  and  plows  are  com- 
parative, not  positive,  in  their  character  and  attainments. 
Before  determining  in  any  given  case  just  what  mill  should 
be  adopted  the  circumstances  should  be  known.  If  the 
tanner  has  purely  hemlock  bark  or  purely  oak  bark,  and, 
moreover,  if  these  barks  vary  in  condition,  being  sometimes 
damp  or  wet  and  at  other  times  dry,  these  conditions  should 
be  known  before  an  intelligent  opinion  can  be  given  as  to  his 
wants. 

For  the  grinding  of  all  kinds  of  barks,  with  the  most  varia- 
ble conditions,  I  judge  that  the  "double  grinder,"  formerly 
known  as  the  "  Starbuck  "  or  "  Troy"  mill  is  preferable.  The 
patent  on  this  kind  of  mill  has  long  since  run  out,  and  it  is 
now  manufactured  at  various  tanning  centers,  but  while  all 
are  essentially  the  same  in  construction,  their  "  fitting  up " 
makes  the  difference  between  a  serviceable  or  worthless  mill. 
A  double  grinding  mill,  carefully  fitted,  will  grind  damp  or 
wet  bark  with  more  success  than  any  other  mill,  and  for  the 
reason  that  its  grinding  surfaces  are  open — set  with  obtuse 
angles — rather  than  close,  with  sharp,  acute  angles.  There 
is  no  reason  why  this  mill  may  not  always  hold  a  respectable 
position  among  tanners  when  proper  care  is  bestowed  upon 
the  castings  and  fittings. 

The  most  artistic,  and,  on  the  whole,  the  most  economical 
mill  yet  presented  for  our  adoption  is  the  mill  made  by 


THE  LEATHER  MANUFACTURE.  49 

Messrs.  Wm.  F.  Mosser  &  Co.,  of  AJlentown,  Pa.  This  mill, 
at  first,  costs  about  $70  to  $80,  but  may  be  renewed  for 
from  $6  to  $10  for  an  indefinite  period.  The  principle  on 
which  it  is  constructed  must  be  approved  by  all,  and  cannot 
fail  to  be  generally  adopted.  Its  large  cost  lies  mainly  in  the 
original "  fitting  up."  The  shaft  or  spindle  is  made  of  wrought 
iron  (or  should  be  so  made),  and  is  carefully  turned  at  its 
bearings.  The  bowl  and  curb  are  also  turned  true,  and  seg- 
ments, either  of  cast  iron  or  steel,  are  bolted  on  these  turned 
surfaces.  This  form  of  construction  gives  a  true  and  adjust- 
able grinding  surface  which  leaves  nothing  to  desire.  These 
segment  surfaces  can  be  either  sharpened  with  a  cold  chisel, 
or  a  "saw  gummer"  run  by  power,  or  may  be  renewed  with 
new  iron  or  steel  segments,  for  the  inconsiderable  sum  above 
named.  The  original  cost  of  a  mill  then  is  of  small  conse- 
quence. It  is  the  cost  of  frequent  renewals  that  makes  the 
expense  of  grinding  with  such  mills  so  great.  By  far  the 
largest  replacement  is  made  necessary  by  breakage,  and  not 
by  wear,  and  hence  the  importance  in  saving  the  original  and 
more  costly  structure.  This  is  done  in  the  case  of  this  mill 
by  a  safety  coupling,  which  renders  breaking  by  the  usual 
casualties  impossible. 

So  confident  was  the  possessor  of  one  of  these  mills  that 
no  accident  would  result  by  throwing  in  iron,  that,  in  my 
presence,  and  against  my  earnest  protest,  he  threw  in  an  iron 
bolt  with  the  bark.  In  a  moment  a  slight  "  click  "  was  heard. 
The  mill  stopped,  but  the  driving  shaft  went  on.  The  coup- 
ling only  had  broken  (this  being  the  weakest  point).  This 
coupling  costs  only  seventy-five  cents.  In  ten  minutes  the 
step  of  the  mill  was  lifted  into  a  new  coupling,  the  iron 
picked  out,  and  the  mill  stMrted  as  usual. 

If  this  safety  coupling  can  always  be  relied  upon,  then,, 
beyond  the  original  cost,  a  new  mill  can  at  all  times  be. 


50  THE  LEATHER  MANUFACTURE. 

procured  of  iron  for  $6,  or  of  steel  for  f  10,  and  this  replace- 
ment is  made  necessary  only  after  repeated  sharpening  of 
the  grinding  surfaces  by  the  ready  means  already  indica- 
ted. Two  hours  will  suffice  for  removing,  grinding  and  re- 
placing one  set  of  these  segment  surfaces,  and  so  true  do  the 
mills  run  that  they  will  "  crack  corn  "  successfully,  or  would 
be  acceptable  coffee  grinders  for  a  large  army  of  men. 

There  is  one  thing,  however,  that  these  mills  will  not  do. 
They  cannot  successfully  grind  damp  or  wet  bark,  and  it  may 
be  doubted  whether,  in  the  nature  of  iron-mill  construction, 
a  close  and  fine  bark  grinder  can  be  made  to  perform  this 
difficult  service.  This  is  a  problem  at  which  the  owners  of 
the  mill  are  now  at  work.  Whether  they  succeed  or  not,  it 
is  certain  they  now  have  the  best,  and,  all  things  considered, 
the  cheapest  bark  mill  known  in  this  country,  and  for  the 
grinding  of  dry  bark  it  leaves  nothing  to  desire. 

It  has  always  been  difficult  in  practice  to  secure  absolute 
uniformity  in  grinding,  even  by  the  newest  and  best  iron 
mills.  The  defects  of  grinding  can  be  overcome  by  the  erec- 
tion of  a  screen  or  wire  sieve,  stretched  over  a  revolving 
skeleton  frame  of  wood.  The  meshes  should  be  three-six- 
teenths of  an  inch  square,  and,  thus  constructed,  may  be  re- 
lied on  to  "  bolt  out  "  all  the  coarse  particles,  and  send  them 
back  to  the  mill  to  be  reground.  This  inexpensive  contriv- 
ance will  cover  the  defect  of  leaving  too  coarse  particles  in 
the  ground  bark,  whether  these  come  from  an  imperfect  mill 
or  an  old,  worn-out  one,  and  no  tanner  can  safely  do  without 
it.  With  the  "  Allentown  mill "  the  screen  will  have  less  to 
do,  but  even  with  this  uniform  grinder  a  screen  is  useful. 
With  a  properly  constructed  screen,  almost  any  mill,  what- 
ever its  condition,  may  be  trusted,  as  its  defects  can  never 
reach  the  leach. 

The  limited  service  now  performed  by  this  screen  only  par- 


THE  LEATHER  MANUFACTURE.  51 

tially  indicates  its  possible  usefulness.  There  is  no  reason 
why  all  the  bark  from  the  mill  may  not  go  into  a  tight  inclos- 
ure  supplied  with  wire  "  bolts  "  or  screens  that  will  make  as 
many  classifications  of  the  ground  bark  as,  in  the  judgment 
of  the  tanner,  are  demanded.  The  dust  should  be  sent  to  a 
leach  made  specially  to  extract  its  strength.  This  may  be  a 
revolving  square  or  round  leach,  with  inside  projections  to 
agitate  the  contents,  or  may  be  a  leach  with  a  round  bottom, 
with  a  paddle  wheel  revolving  on  and  in  its  top  surface,  for 
the  purpose  of  keeping  for  a  time  the  dust  floating  in  the 
weak  liquor  or  water.  This  bark  dust  so  readily  yields  up 
its  tannin  that  almost  any  contact  with  warm  water  will  suf- 
fice to  denude  it  of  its  tanning  properties.  When  the  dust  is 
all  separated  from  the  remainder  of  the  bark,  the  leaching 
will  proceed  rapidly,  as  the  circulation  is  less  obstructed. 

Of  course  th  3  ground  bark  of  this  screening  process  can  be 
graded  to  suit  either  the  leach  or  the  layaways.  The  latter 
service  requires  a  much  coarser  bark  than  the  former,  and,  by 
careful  screening,  bark  of  any  particular  size  which  may  be 
needed  can  be  obtained. 

The  question  is  often  mooted  as  to  the  degree  of  fineness 
to  which  bark  may  be  reduced  for  advantageous  leaching. 
The  answer  is,  as  fine  as  the  "percolation"  or  "press  sys- 
tem "  of  leaching  will  permit.  If  all  bark  could  be  reduced 
to  a  uniform  size,  "buckwheat"  or  "cracked  corn"  would 
nearly  represent  the  condition  most  favorable  for  the  ready 
and  economic  extraction  of  the  tannin  from  the  bark. 

"Within  a  few  months  another  example  of  "  saw  grinding  " 
or  cutting  of  bark  for  tanners'  use  has  come  to  my  attention. 
The  work  performed  by  this  machine  is  admirable,  and  if 
done  with  the  ease  and  rapidity  stated  by  those  interested, 
then  it  promises  to  divide  with  the  best  bark  grinder  the 
patronage  of  our  tanners.  The  promoters  of  this  sawing  ma- 


52  THE  LEATHER  MANUFACTURE. 

chine,  however,  seem  to  think  that  their  machine  is  new.     In 
construction  it  may  be,  but  not  in  principle. 

The  numerous  other  mills  made  are  not  here  mentioned, 
not  because  they  have  no  merit,  but  mainly  because  their 
advantages  are  so  varied  and  disproportionate  to  their  num- 
ber that  it  would  take  up  too  much  space  and  time  for  their 
presentation.  Most  of  the  bark  mills  which  have  considera- 
ble merit,  aod  have  been  largely  introduced  to  the  trade, 
have  had  their  specially  commendable  points  presented  to 
our  tanners  through  the  columns  of  the  Shoe  and  Leather  Re- 
porter during  several  years  past.  But  the  writer  has  these 
suggestions  to  make  to  bark  mill  manufacturers :  Take  great 
pains  in  fitting  up  your  mills  ;  make  your  grinding  surfaces 
replaceable,  and  have  them  run  true,  so  that  what  bark  goes 
through  is  not  ground  to  a  powder,  but  in  uniform  particles  ; 
adopt  a  safety  coupling,  so  that  a  valuable  and  even  a  high 
cost  mill  can  be  indulged  in  by  all  tanners  at  an  inconsidera- 
ble aggregate  outlay. 

On  this  subject  it  now  only  remains  to  call  attention  to  a 
"bark  crushing"  and  "extracting"  machine,  which  came  to 
the  attention  of  tanners  a  few  years  ago,  but  has  now  been 
forgotten  by  its  failure,  and  is  here  mentioned  to  call  atten- 
tion to  the  fact  that  bark  crushing,  like  bark  sawing,  has  been 
tried.  This  machine  was  a  most  ponderous  affair.  It  con- 
sisted of  a  series  of  metal  rollers,  through  which  the  un- 
ground  bark  (bark  in  the  leaf)  was  passed  after  having  been 
soaked  in  hot  water  for  an  hour  or  more.  It  was  claimed  for 
this  process  of  squeezing  that  nothing  but  the  fine  "salts" 
would  come  out,  leaving  all  the  resin  and  much  of  the  color- 
ing matter  behind.  The  report  which  was  made  on  the  prac- 
tical working  of  this  costly  experiment  was  to  the  effect  that 
the  bark  (hemlock)  was  thoroughly  crushed,  and  a  portion  of 
the  tannin  was  squeezed  out,  but  that  much  remained.  It 


THE  LEATHEK  MANUFACTTJKE.  53 

was  conceded  that  the  bark  was  most  admirably  prepared  for 
leaching,  being  left  in  the  form  of  a  "pulp."  But  the  ma- 
chine was  expensive,  costing  fully  $1,000,  besides  requiring 
30-horse  power  to  drive  it,  and,  while  interesting  as  an  ex- 
periment, was  a  failure  for  practical  work.  When  last  heard 
from  this  machine  belonged,  to  a  corporation  or  association, 
and  was  started  in  Tennessee  to  make  oak  extract. 

It  is  quite  common  for  patentees  and  even  tanners  to  over- 
estimate the  amount  of  bark  ground  per  day  or  hour  by  their 
mills.  It  is  a  good  mill  that  will  average* one  cord  per  hour, 
although  we  hear  reports  of  the  grinding  of  one  and  a  half 
and  even  two  cords  per  hour.  But  bark  ground  at  the  rate 
of  one  cord  per  hour  and  well  done  is  far  more  profitable 
than  more  rapid  work.  The  writer  has  seen  a  mill  grind  one 
cord  in  fourteen  minutes.  The  mill  was,  however,  "geared 
up"  to  280  revolutions  per  minute,  and  ground  the  bark  very 
coarse  at  that. 

This  leads  me  to  say  that  a  slow  motion  is  desirable.  It  is 
questionable  whether  a  motion  of  over  eighty  revolutions  per 
minute  is  either  profitable  or  effective  ;  certainly  the  benefits 
can  in  no  wise  overbalance  the  defects  in  grinding  and  dan- 
ger of  fire  arising  from  excessive  friction.  A  quick  motion 
has  the  effect  to  "throw  up"  and  "back"  the  bark,  rather 
than  to  take  it  in  and  pass  it  through  the  grinding  surfaces, 
as  a  slower  motion  will.  The  best  experience  has  demon- 
strated that  eighty  revolutions  on  a  small  and  seventy  revo- 
lutions on  a  large-size  mill  is  the  proper  motion.  Any  faster 
motion,  besides  the  loss  of  power  involved,  will  not  propor- 
tionately increase  the  result,  and  will,  besides,  greatly  in- 
crease the  fire  risk. 

The  time  may  come  when  hemlock  and  oak  bark  will  be- 
come so  scarce  and  dear  as  to  necessitate  other  means  than 
grinding  and  leaching  for  getting  the  strength  out.  It  is  now 


54  THE  LEATHER  MANUFACTURE. 

est  mated  that  from  7  to  10  per  cent,  of  the  strength  is  left  in, 
and  it  has  been  doubted  whether  any  of  our  present  methods 
will  take  out  that  small  remainder  profitably.  The  English 
tanner,  who  pays  from  £5  to  £7  per  ton  for  his  bark,  would 
pitch  the  leach  over  once  or  twice,  releaching  each  time  until 
the  last  particle  of  strength  was  out.  The  German  tanner 
would  use  his  bark  on  his  lay  away  s  for  two  or  three  months, 
and  then  take  the  last  strength  out  by  leaching.  All  these  pro  • 
cesses  are  so  different  from  ours  that  we  cannot  avail  our- 
selves of  their  tedious  methods.  The  time  may  come  when 
it  will  pay  to  pass  the  partially  spent  tan  through  metal  roll- 
ers, thus  breaMng  and  crushing  the  unspent  portions.  So 
far  as  the  power  is  concerned,  this  could  be  afforded  now ; 
but  the  labor  of  passing  the  tan  out  of  the  leach  and  through 
these  rollers,  and  then  again  back  into  the  leach,  would  cost 
more  than  the  small  percentage  of  strength  gained  would  be 
worth. 

Some  illustrations  of  bark  mills,  and  sectional  parts  of 
mills,  with  further  description  of  their  working,  will  be 
found  in  subsequent  pages. 


CHAPTEK    VI 
LEACHING. 

TANNIN  VS.  EESINOUS  AND  COLORING  MATTER TANNIN   REQUIRED  TO  MAKE 

GOOD   WEIGHT EXTREME    HEAT   IN   LEACHING   INJURIOUS FLOODING 

THE  BARK THE    PRESS   LEACH HEAT   TO    BE   APPLIED  ONLY  TO    THE 

WEAKEST  LEACH CONSTRUCTION  OF  LEACHES CLAY  AND  LOAM  PACK- 
ING FOR  THE  SIDES  AND  BOTTOMS WORKING    THE  PRESS  LEACH THE 

SPRINKLER  LEACH REVOLVING  DETACHED  LEACH. 

The  full  and  perfect  extraction  of  all  the  tannin  from  the 
bark  is  not  only  desirable,  but  is  of  primary  importance  ;  it 
is  equally  essential,  however,  that  this  subtle  elixir  should  be 
extracted  without  deterioration  or  injury.  It  is  found  in 
practice  not  at  all  difficult  to  wash  out  all  the  extractive  or 
soluble  matter  from  bark,  but  to  separate  and  take  out  the 
greatest  amount  of  tannin,  leaving  the  largest  portion  of  col- 
oring and  resinous  matter  behind,  is  quite  a  different  thing, 
and  one  which  has  taxed  the  efforts  of  our  best  tanners.  The 
system  of  leaching  which  will  best  enable  the  tanner  to  con- 
trol and  separate  these  qualities  is,  in  my  judgment,  the 
one  to  be  most  commended.  In  fairness  it  ought  to  be  said, 
however,  that  there  is  much  difference  of  opinion  on  this  sub- 
ject among  some  of  our  largest,  and,  financially,  the  most  suc- 
cessful of  our  tanners. 

Their  theory  and  practice  must  proceed  on  the  assumption 
that  coloring  matter  will  give  weight,  when  incorporated  with 
the  hide,  and  that  the  resinous  matter  will  in  some  mysteri- 


56  THE  LEATHER  MANUFACTURE. 

ous  way  attacli  itself  to  the  leather,  defying  the  action  of  the 
scrubber  to  wash  it  out.  This,  to  the  writer,  is  a  dangerous 
heresy,  and  should  be  rejected  unless  there  are  facts  and 
considerations  favoring  it  which  have  never  been  presented 
to  the  public,  for  to  it  may  be  justly  charged  all  the  defects 
in  color  which  for  so  m-uiy  years  baffled  our  hopes  of  a  suc- 
cessful foreign  market.  It  has  also  caused  other  defects, 
both  of  finish  and  quality,  which  it  will  be  more  appropriate 
to  consider  in  another  place. 

The  commencement  and  successful  continuance  of  the 
"union"  sole  leather  trade,  both  in  "crop"  and  "sides,"  has 
demonstrated  that  it  is  possible  to  make  a  light,  fair  color 
while  using  hemlock  bark.  With  such  experience  as  the  man- 
ufacture of  this  description  of  leather  furnishes,  the  writer  is 
prepared  to  defend  the  position  here  assumed,  viz.,  that  tan- 
nin, and  not  coloring  or  resinous  matter,  enters  the  fiber  and 
gives  weight.  All  the  illustrations  or  seeming  proofs  to  the 
contrary  are  drawn  from  heavy  sole  leather  tannages.  There 
is  an  inherent  inequality  in  the  conditions  of  the  two  kinds 
of  tannage  which  will  fully  account  for  the  disparity  in  weight 
made  under  each,  quite  independent  of  the  conditions  wo 
are  combatting.  It  would  be  unfair  for  me  to  assume 
the  correctness  of  my  theory  from  the  fact  that  a  given 
quantity  of  bark  will  make  more  light  colored  leather  than 
dark,  for  bark  will  go  further,  as  all  know,  in  light  weight 
tannages  than  in  heavy.  This  is  illustrated  by  the  well- 
known  fact  that  one  ton  of  hemlock  bark  will  tan  300  pounds 
of  upper  leather,  while  it  will  only  tan  200  pounds  of  sole 
leather.  It  would  be  as  unfair  for  me  to  assume  that  this 
difference  was  creditable  to  the  absence  of  the  extra  coloring 
and  resinous  matter,  as  it  would  be  for  those  who  differ  from 
me  to  assume  the  opposite  conclusion. 

The  success  and  value  of  any  system  of  leaching  must  de- 


THE  LEATHER  MANUFACTURE.  57 

pend  upon  the  intrinsic  or  serviceable  value  of  the  liquor  or 
extract  obtained.  If  liquor  obtained  from  the  bark  without 
heat  will  make  leather  that  will  bring  in  the  market  one  cent 
per  pound  more  than  leather  made  with  an  extract  obtained 
by  extreme  heat,  then  it  is  clear  that  a  cold  or  more  moder- 
ate process  is  preferable  to  the  hot  water  or  steam  process, 
provided  all  the  other  conditions  are  equal. 

The  "union  crop"  leather  tanners  have  learned  to  compre- 
hend the  value  of  moderate  instead  of  extreme  heat,  and  when 
better  methods  of  grinding  and  screening  the  bark  shall  be 
appreciated  at  their  full  value,  even  less  heat  than  at  present 
will  be  employed  by  them ;  the  more  nearly  summer  heat 
(60°)  is  adhered  to  on  the  head  leach,  the  more  modified  and 
controllable  will  be  the  color.  This  view  of  leaching  was 
maintained  by  Mr.  James  Clewer*  during  all  his  American 
experience,  and  it  must  be  conceded  that  he  produced  as 
satisfactory  results  as  any  tanner,  either  before  or  since  his 
time.  He  frequently  demonstrated  his  ability  to  make  190 
to  200  pounds  of  leather  with  one  ton  or  cord  of  bark,  and 
he  never  used  more  than  summer  heat  on  his  head  leach  ex- 
cept in  winter. 

There  have  been  during  the  past  forty  or  fifty  years  a  great 
variety  and  many  forms  of  leaches  and  leaching  processes. 
Previous  to  this  period,  viz.,  about  1820,  leaches  were  not 
used  to  any  considerable  extent  for  new  bark.  A  single  vat 
was  set  apart  into  which  all  the  old  layaway  bark  was  cast 
for  final  washing,  but  this  was  the  extent  of  the  leaching 
process  ;  and  if  the  writer's  observation  and  information  can 
be  relied  upon  this  sytem  prevails  now  in  most  of  the  coun- 

*An  English  tanner  who  came  to  this  country  ahout  the  year  1829.  He  was  a 
practical  workman,  and  had  as  thorough  an  understanding  of  the  true  principles 
of  good  tanning  as  almost  any  one  in  the  trade  at  that  time,  either  in  this  country 
or  Great  Britain.  His  work  and  experiments  among  our  tanners  were  of  lasting 
value  in  materially  advancing  the  trade  in  many  particulars. 


58  THE  LEATHER  MANUFACTURE. 

tries  in  Southern  Europe.  No  country  now  so  universally 
employs  leaches  as  our  own  ;  and,  therefore,  we  can  draw  no 
lessons  from  their  larger  experience,  as  in  many  of  the  other 
departments  of  our  leather  manufacture. 

There  are  in  this  country  three  distinct  systems  or  meth- 
ods employed  for  leaching  bark,  but  a  much  greater  variety 
of  forms.  For  the  sake  of  designation  we  may  call  the  first 
a  "  douse,"  the  second  a  "  press,"  and  the  third  a  "  sprinkler  " 
leach.  The  douse  leach  is  the  oldest  known  method.  It  is 
the  one  used  from  1824  to  1832  by  the  hemlock  tanners  who 
made  their  way  into  Greene,  Delaware  and  Schoharie  coun- 
ties, in  the  State  of  New  York,  at  that  early  period  of  our 
tanning  history.  Usually  one  leach  was  placed  on  the  top 
of  another.  The  top  leach  had  a  heater  of  some  form  con- 
tained within  it,  by  which  the  liquor  and  bark  were  "  heated 
up,"  even  to  the  boiling  point,  and  the  liquor  was  finally 
dropped  down  on  a  leach  below,  usually  also  containing  bark, 
but  not  always,  for,  when  stationary,  it  was  found  difficult  to 
so  run  them  as  to  wash  properly  the  weaker  bark ;  usually 
the  upper  and  lower  leaches,  however,  were  filled  at  the  same 
time,  and  worked  together  as  one  leach.  Any  leach,  or  sys- 
tem of  leaching,  may  be  said  to  belong  to  this  class  that 
floods  the  bark  and  allows  the  whole  bulk  to  remain  saturated 
and  stationary.  Even  where  the  leaches  are  pumped  over 
from  one  to  the  other,  if  the  contents  are  allowed  to  stand, 
and  the  liquor  is  then  drawn  off  in  bulk,  the  leach  belongs  to 
this  class. 

The  "  press"  leach  was  introduced  into  this  country  by  Mr. 
James  Clewer,  about  1830,  and  the  method  was  improved,  by 
his  own  suggestions,  from  some  leaches  which  he  had  worked 
in  England.  His  system  washes  out  the  extractive  matter, 
including  the  tannin,  "by  column,"  as  contradistinguished 
from  the  "  sprinkling  "  or  percolating  method  introduced  by 


THE  LEATHEB  MANUFACTURE.  59 

Allen  &  Warren,  which  is  the  third  distinct  process,  as  is 
claimed ;  and  yet  it  will  be  seen  by  close  observation  that 
these  last  two  methods  resemble  each  other  very  much  in 
principle,  since  both  move  constantly  from  the  weaker  to  the 
stronger  bark.  The  one  passes  by  column  and  the  other  by 
percolation,  and  that  is  the  only  difference. 

Keeping  in  view  the  three  general  divisions  or  classifica- 
tions of  leaches,  let  us  go  back  and  consider  them  in  their 
order.  The  douse  leach  may  be  of  any  size  or  construction. 
It  may  be  round  or  square.  It  may  be  filled  with  bark  and 
the  liquor  or  water  run  on,  or  the  bark  may  be  run  on  with 
the  liquor  (floated  from  the  mill).  This  leach  may  be  heated 
up  in  any  way,  either  by  inserting  steam  under  the  false  bot- 
tom, or  the  liquor  or  water  may  be  heated  before  it  is  run  on. 
This  process  of  flooding  and  "running  up"  and  "  off,"  either 
with  or  without  heating,  is  even  now  much  practiced,  and, 
but  for  the  fact  that  it  tends  to  dilute  the  liquors  in  the  yard, 
is  very  satisfactory.  But  this  dilution,  or  want  of  concentra- 
tion, is  an  evil  which  all  tanners  deplore  and  desire  to  avoid 
in  heavy  tannages.  For  upper,  harness,  and  calf,  it  will  do 
better  service ;  but,  for  reasons  presently  to  be  stated,  there 
is  less  thoroughness  in  the  leaching  than  by  either  of  the 
other  methods,  for  it  must  be  evident  that  the  discarded  bark 
must  have  retained  the  strength  of  the  last  liquor  that  has 
passed  off,  and  for  this  reason  can  never  be  perfectly  denuded 
of  its  tannin. 

The  usual  or  best  form  of  constructing  and  working  the 
press  leach  may  be  stated  as  follows  :  The  number  of  leaches 
in  a  set  should  correspond  to  the  number  of  days  in  the  week, 
or  the  number  of  full  leaches  required,  multiplied  by  the 
number  of  days  in  the  week,  thus,  6, 12,  18  or  24.  According 
to  my  judgment,  six  leaches  in  a  set  are  always  better  than 
any  other  number.  By  this  plan  one  new  leach  is  filled  in 


60  THE  LEATHER  MANUFACTURE. 

each  set  each  day  of  the  week,  and  if  more  than  the  capacity 
of  one  leach  is  required  for  the  day's  work,  then  the  sets  of 
leaches  should  be  multiplied,  rather  than  to  break  into  the 
system  as  here  contemplated.  This  will  give  at  least  five 
days  for  the  leaching  of  all  the  bark,  and  this  time  is  ample 
and  more  than  enough.  Too  many  tanners,  however,  when 
crowded,  break  into  their  plan,  and  attempt  to  force  two 
leaches  a  day  from  a  single  set,  which  creates  confusion  and 
leads  to  waste. 

Under  no  circumstances  is  heat  applied  to  any  other  than 
the  back  or  weakest  leach.  This  will  bring  the  strong  liquor 
of  the  set  on  the  head  leach  comparatively  cold,  or  at  most 
at  summer  heat.  Such  a  course  will  bring  all  the  liquors 
passing  through  the  yard  into  a  proper  condition  to  go  upon 
the  leather  without  coolers  or  waiting.  It  will  also  do  much 
more ;  it  will  leave  behind  much  of  the  coloring  and  resinous 
matter,  and  send  forward  a  pure  tan  liquor,  free  from  all  sedi- 
ment and  impurities. 

The  form  may  be  square  or  round,  depending  on  the  situ- 
ation of  the  ground  where  placed.  Where  it  is  possible,  this 
kind  of  leach  should  be  set  in  the  ground  on  a  level,  and  well 
filled  in  with  clay  or  loam.  Exceptionally  the  writer  has  seen 
them  set  on  a  side  hill — one  raised  six  or  eight  inches  above  the 
other — but  it  is  safe  to  say  fchat,  when  placed  in  sets  of  not 
more  than  six,  there  will  be  no  difficulty  in  working  the  press. 
When  placed  in  the  ground  and  filled  in  with  loam,  they 
should  be,  in  size,  6  by  6,  8  by  8, 10  by  10,  12  by  12  feet,  etc., 
their  capacity  being  regulated  by  the  size  of  the  vats  in  the 
yard. 

It  may  be  well  here  to  mention  a  fact  that  is  not  generally 
known,  viz.,  that  loam  is  quite  as  good  as  clay  for  pack- 
ing for  the  sides  and  bottoms  of  the  leach,  if  only  properly 
prepared.  The  preparation  consists  in  mixing  the  earth  with 


THE  LEATHER  MANUFACTURE.  61 

water  to  the  consistency  of  thin  mortar  in  a  vessel  before  it 
is  poured  in  between  the  vats  or  leaches.  If  so  mixed  and 
run  in,  a  solid  sandstone  formation  will  result.  To  be  con- 
vinced of  the  efficiency  of  this  method  of  filling  in  between 
leaches,  try  this  experiment :  Take  an  ordinary  pail  and  fill 
it  with  loam  ;  while  doing  so  pour  in  water,  so  that  when 
filled  there  will  be  a  thick  earthy  substance  ;  stir  up  well  and 
let  it  stand  for  one  day.  The  water  will  all  be  on  the  top, 
and  the  earthy  portion  will  have  gone  to  the  bottom,  each 
particle  in  its  order  of  specific  gravity.  These  particles  will 
so  compactly  adjust  themselves  as  to  form  a  solid  stone.  In- 
deed, geology  informs  us  that  this  is  the  way  that  sandstone 
is  formed  in  the  earth.  You  may  bore  any  number  of  holes 
in  the  bottom  of  the  pail,  but  no  water  can  pass.  The  water 
will  in  time  evaporate  from  the  top,  but  cannot  escape  other- 
wise. Unless  great  care  is  observed  this  concrete  will  force 
the  sides  of  the  vats  or  leaches  in  ;  or,  still  worse,  raise  them 
from  the:'r  beds,  by  working  under  and  pressing  them  up. 
To  avoid  this,  water  should  be  run  in  to  fill  the  vats  as  fast 
as  the  concrete  fills  the  outer  sides  or  passages  around  and 
between.  It  is  never  safe  to  trust  to  studding  to  keep  the 
new  and  empty  vats  in  place.  Mr.  James  Clewer  used  this 
loam  filling  with  such  effect  as  to  render  corking  unnecessary. 
But  he  was  careful  to  have  tight  joints  before  battening. 

The  "  covering  "  of  liquor  of  one  leach  should  in  quantity 
supply  one  or  two  liquors  for  the  layaway.  There  should 
be  no  fraction  or  portion  left  over.  The  leaches  should 
be  made  of  hemlock  or  pine  plank,  not  less  than  two  inches 
thick,  battened  together  and  corked.  Two  days'  work  will 
make  a  leach  10  by  10,  and  one  day  will  cork  it.  This  is 
additional  to  the  preparation  of  the  ground  and  the  after 
filling  with  loam. 

Bound  leaches  are  recommended  when  it  is  inconvenient  to 


62  THE  LEATHER  MANUFACTURE. 

place  them  under  ground.  These  are  uiore  expensive  in  the 
first  cost,  and  will  la-t  hardly  more  than  four  years  if  made 
of  hemlock,  and  five  or  six  if  made  of  pine;  but  by  reason 
of  the  more  rapid  action  of  the  sprinkling  process  it  is  claimed 
that  one-quarter  of  the  leach  capacity  under  that  system  will 
give  the  full  result  of  the  less  active  press  system,  and  this 
statement  is  probably  well  founded. 

Bound  leaches  may  be. used  on  the  press  principle,  but  the 
square  leach  cannot  very  well  be  used  by  the  Allen  &  War- 
ren, or  sprinkling  process,  although  some  attempts  of  this  kind, 
moderately  successful,  have  come  to  my  knowledge.  In  this 
general  statement  it  is  supposed  that  the  reader  understands 
the  method  of  making  round  as  well  as  square  leaches,  and 
of  connecting  them,  both  from  above  and  below,  with  the  junk 
yard,  waste  conductors,  etc.;  therefore,  mention  is  made  in 
detail  only  of  such  points  in  regard  to  the  connections  of  the 
press  leach  as  are  peculiar  to  its  system  of  working. 

Let  us  suppose  six  leaches  all  placed  on  a  level,  each  of 
them  having  %  false  bottom,  and  constructed  in  the  usual  way. 
Each  of  these  leaches  have  a  tight  conductor  leading  from 
under  the  false  bottom  up  to  the  top  of  the  leach — so  tight 
as  to  prevent  the  passage  of  any  liquor  except  such  as  has 
been  through  the  circuit  and  down  under  the  false  bottom. 
If  these  tight  tubes  or  conductors  are  placed  in  opposite  or 
alternate  corners  of  the  leach,  it  will  often  prevent  currents, 
which  are  likely  to  form  if  they  are  otherwise  placed.  The 
effect  of  placing  a  tight  tube  in  this  position  is  of  course  to 
cause  that  tube  to  be  always  filled  with  such  liquor  only  as 
has  passed  through  all  the  bark,  and  is  tqual  in  strength  to 
that  standing  under  the  false  bottom;  it  will,  besides,  stand 
on  a  level  with  the  liquor  in  the  leach,  and  will  overflow  when 
it  reaches  up  to  the,  opening  which  leads  to  the  next  adjoin- 
ing leach.  These  openings  should  be  about  8  to  10  inches 


THE  LEATHER  MANUFACTURE.  63 

from  the  top  in  each  leach,  and  about  2  inches  in  diameter  ; 
if  the  openings  are  oval  or  oblong,  all  the  better.  To  prevent 
currents  forming  it  is  usual  to  cover  the  bark  with  boards,  so 
that  the  liquor  will  spread  over  the  whole  surface  and  press 
from  the  top.  But  if  the  system  is  worked  uniformly  there 
will  be  no  difficulty  from  currents  forming.  It  is  always  safe, 
when  the  leach  is  filled  with  new  bark,  to  carefully  level  it  off 
and  cover  the  whole  surface  with  boards  perforated  with  inch 
holes,  the  whole  to  be  battened  down,  so  as  to  hold  the  bark 
in  place.  These  board  coverings  answer  the  double  purpose 
of  holding  the  dry  bark  from  rising  (floating)  and  spreading 
the  weak  liquor  gently  over  the  whole  surface. 

"Warm  water  or  liquor  is  more  expanded  and  consequently 
lighter  than  cold.  Strong  liquor  is  heavier  than  weak  liquor. 
Now,  if  we  put  the  two  light  conditions  together,  viz.,  hot  and 
weak,  and  place  them  on  top  of  the  heavy  and  cold  liquor, 
they  will  remain  separate  for  all  time,  or  so  long  as  these  un- 
equal conditions  are  maintained.  A  simple  experiment  with 
water  and  tan  liquor  in  a  tumbler  will  demonstrate  this  prac- 
tical result.  Weak  tan  liquor  will  stand  all  day  on  the  top  of 
strong  and  heavy  liquor,  if  not  agitated.  Now,  if  to  the  weak 
liquor  we  add  heat,  the  separation  will  be  still  more  marked. 
A  tumbler  half  filled  with  weak  and  warm  liquor  may  be 
forced  out  of  the  top  by  gently  inserting  strong  and  cold 
liquor  underneath  by  means  of  a  pipe.  The  action  of  these 
bodies,  if  the  experiment  is  carefully  made,  will  satisfy  any 
one  that  the  system  of  press  leaching  can  be  carried  on  with- 
out mixing  the  liquors  on  their  passage,  if  the  system  here 
recommended  is  followed. 

The  six  leaches  should  at  all  times  be,  equally,  from  two- 
thirds  to  three-quarters  full  of  bark,  and  stand  covered 
with  liquor  varying  in  strength  with  the  strength  of  bark  in 
each.  Let  us  suppose  that  the  head  leach  has  just  been  filled 


64  THE   LEATHER  MANUFACTURE. 

with  fresh  ground  bark;  the  last  or  back  ]each  is  then  full  of 
spent  tan  ready  to  pitch,  and  the  intermediate  four  leaches 
are  divided  both  as  to  strength  of  liquor  and  age  of  bark  from 
these  two  points.  No  liquor  is  sent  into  the  yard  except 
from  the  top  of  the  head  leach,  and  where  very  strong  liquors 
are  needed  only  one  liquor  is  so  sent  from  each  head  leach,  so 
that  the  accumulated  strength  of  all  the  bark  in  one  leach  is 
concentrated  in  this  one  liquor.  If  a  less  degree  of  strength 
is  required,  then  two  runs  may  be  taken  off,  and  in  excep- 
tional cases  even  three  or  four.  The  liquor  thus  sent  into 
the  yard  is  not  returned  until  all  the  strength  is  taken  from 
it,  and  is  then  either  sent  off  into  the  stream  as  worthless  or 
sent  again  to  the  back  leach  after  passing  through  the  heater, 
and  heating  up  to  100°  or  120°  of  heat.  The  spent  liquor, 
with  its  accumulated  acid,  should  go  back  again  into  the 
leaches  for  further  use  if  the  tanner  is  making  sole  leather, 
and  should  go  off  into  the  stream  if  light  leather,  such  as 
calf,  kip,  or  even  harness,  is  to  be  tanned. 

If  this  system  is  carried  out  each  layer  or  particle  of  bark 
must  be  washed  as  many  times  as  the  whole  bulk  exceeds  the 
number  of  these  particles  or  layers.  Suppose  the  leach  to  be 
six  feet  deep,  and  to  be  filled  four  feet  with  bark.  If  the  cov- 
ering of  liquor  is  represented  by  the  remaining  two  feet  (prac- 
tically it  will  be  more  than  this),  then  each  layer  of  an  inch 
will  have  these  two  feet  of  water  pass  through  its  particles  by 
corresponding  portions  of  this  liquor.  So  that,  in  fact,  the 
number  of  times  each  particle  of  bark  is  washed  by  the  liquor 
on  its  passage  is  almost  infinite.  This  liquor  gathers  strength 
all  the  way  on  its  passage,  both  theoretically  and  practically, 
as  tanners  may  demonstrate  by  taking  samples  from  any 
stage  of  the  progress.  If  the  press  is  properly  worked  the 
result  will  be  the  same  as  if  six  leaches  were  placed  on  the 
top  of  each  other,  and  the  whole  amount  of  liquor  percolated 


THE   LEATHER   MANUFACTURE.  65 

through  all,  or  the  same  as  if  the  bark  was  leached  in  one 
leach  36  feet  deep. 

One  of  the  advantages  of  leaching  by  column  in  this  way, 
rather  than  by  percolation  or  flooding,  is  that  currents  are 
not  so  likely  to  form,  and  the  fine  bark  dust  is  not  forced  to 
the  bottom  to  stop  the  free  passage  of  the  liquor.  Currents 
are  more  liable  to  form  with  any  other  known  mode  of  pass- 
ing liquor  through  bark  than  by  this  method. 

While  the  writer  regards  six  as  the  proper  number  of 
leaches  to  connect  in  one  set,  as  many  as  twenty-four  are 
sometimes  so  connected ;  but  when  so  many  are  connected  it 
necessitates  the  use  of  pumps  to  aid  the  press  by  more  or  less 
forcing  of  the  liquors.  Covering  so  much  space,  with  so  small 
a  v  iriation  in  the  weight  of  liquor  in  the  leaches,  necessarily 
makes  the  flow  sluggish. 

In  regard  to  the  Allen  &  Warren  leach,  perhaps  the  fairest 
way  to  present  its  merits  would  be  to  give  extensive  extracts 
from  the  patentees'  published  circulars.  But  this  would 
carry  me  far  beyond  my  purpose,  which  is  to  indicate  in  the 
fewest  words  the  conceded  merits  of  the  various  methods  of 
leaching.  In  this  view,  it  would  be  unfair  to  hold  this  patent 
accountable  for  all  the  damage  done  by  those  who  use  it. 
There  is  no  reason  why  hot  liquor  or  water  should  be  per- 
colated through  newly-ground  bark,  as  is  the  custom  of  many 
tanners  who  use  this  leach.  Nor  is  there  any  necessity  for 
running  into  the  yard  the  fine  dust  and  sediment  which 
naturally  runs  off  with  the  liquor  through  the  open  lattice 
bottom.  Both  of  these  practices  are  rather  an  abuse  of  the 
system,  which  may  be  avoided.  Cold  liquor  can  be  used  on 
the  new  bark  by  this  process  as  well  as  any  other.  This 
should,  to  follow  the  principle  of  the  press  leach,  be  the 
strongest  liquor  at  the  disposal  of  the  tanner.  If,  for  in- 
stance, a  liquor  of  16°  by  the  barkometer  is  run  on  through, 

5 


06  THE   LEATHER  &ANUFACTUEE. 

the   sprinkler,  it  should   tfcru  off   a  liquor  of   double  that 
strength. 

The  patentees  of  this  form  of  leach  have  laid  d  /wn  certain 
formulas  and  claim  results  which  are  not  usually  attained 
by  tanners,  and  which  the  writer  is  inclined  to  think  are  not 
realized  in  practice.  Their  claims,  then,  which  are  based  on 
superior  results  over  any  other  system,  are  not  realized  No 
tanner  can  get  more  strength  than  all  there  is,  and  there  are 
several  methods  which  practically  accomplish  this. 

This  sprinkler  leach  does  concentrate  liquor  more  than 
any  other  system,  as  it  is  worked,  i.  e.,  a  given  or  limited 
quantity  of  water  will  carry  off  more  tannin  by  this  process 
than  by  any  other.  In  still  other  words,  the  tanner  can  con- 
trol his  strength  better  by  this  method  than  by  any  other. 
For  instance,  the  first  barrel  or  hogshead  of  liquor  which 
percolates  through  may  stand  as  high  as  32°  to  36°,  and 
then  the  strength  begins  to  decrease,  so  that  when  the  bull: 
of  the  leach  has  run  off  the  whole  aggregate  strength  may 
not  be  over  14°  to  16°.  The  tanner  may  stop  at  any  point 
during  this  percolating  process,  and  thus  secure  just  as  little 
bulk  and  just  as  much  strength  as  he  desires.  There  are 
many  forms  of  this  leach,  and  as  many  methods  of  econom- 
ically working  them.  The  newly  patented  form  (the  Mc- 
Kenzie  patent)  now  so  successfully  making  extract  at  Yan- 
dalia,  N.  T.,  is  one  which  is  claimed  to  be  very  economical 
The  leaches  in  this  case  are  round,  and  only  about  three 
feet  deep,  and  are  movable.  The  whole  leach,  when  filled 
with  newly  ground  bark,  is  placed  under  two  others  of  like 
^ize.  The  percolation  continues  through  each  until  the  new 
}  >ark  is  reached.  It  is  claimed  that  these  filled  leaches  are 
handled  by  machinery  so  economically  that  one  man,  or  even 
a  bey,  can  empty  and  replace  a  leach  without  difficulty.  The 
model  indicates  great  ingenuity  and  effectiveness,  but  whether 


THE   LEATHER   MANUFACTURE.  67 

the  saving  of  labor  will  overcome  the  disadvantages  of  cost 
must  be  determined  hereafter. 

The  writer  once  tried  a  series  of  experiments  on  construct- 
ing leaches  that  should  revolve,  and  while  he  had  no  diffi- 
culty in  perfectly  leaching  the  bark,  he  very  much  doubted 
whether  the  saving  of  labor  was  a  sufficient  compensation  for 
the  cost.  The  general  plan  consisted  in  making  a  leach  eight 
feet  square  by  two  feet  deep.  This  would,  when  constructed, 
make  an  inclosure  which  would  hold  one  cord  of  ground 
bark,  weighing  about  5,500  pounds  when  wet,  independ- 
ent of  the  weight  of  the  leach.  This  leach  was  hung  by 
an  iron  gudgeon  firmly  screwed  to  the  center  of  the  flat 
sides  or  strong  timber  framework  of  the  leach.  On  these 
gudgeons  rested  and  turned  this  immense  box  or  leach.  Two 
of  the  ends  were  perforated  full  of  fine  holes,  through  which 
water  or  liquor  was  run  or  percolated  for  a  limited  time,  and 
then  by  reversing  the  leach  all  the  bark  which  had  been 
packed  would  be  loosened  up,  and  the  further  percolation 
could  be  continued.  The  final  pitching  or  casting  of  this 
leach  was  effected  by  opening  a  large  trap  door,  which  would 
allow  all  the  bark  to  drop  on  the  floor  below,  or  it  could  be 
directed  off  into  the  stream  by  a  shute.  Six  hours  of  active 
operation  with  this  leach  sufficed  to  take  all  the  tannin  from 
the  bark.  One  of  these  small  leaches  would  in  twenty-four 
hours  leach  four  cords  of  bark,  with  very  little  labor.  But 
there  is  considerable  machinery  and  wear  and  tear  to  this  or 
;iny  other  kind  of  detached  leach,  and  while  they  may  be  suc- 
cessful theoretically,  practically  the  writer  cannot  commend 
llieir  use,  with  his  present  experience. 


CHAPTEE    VII. 
HANDLING. 

THE   HAND   REEL THE  EOCKER  HANDLER ITS    CONSTRUCTION  AND   OPERA- 
TION  IMMERSED   DRUM  WHEELS A  METHOD  OF  RAISING  HIDES   FROM 

THE   HANDLER   VATS THE  TUB  WHEEL   HANDLER HANGING  HIDES  IN 

THE  HANDLERS THE  "ENGLAND"  WHEEL HANDLING  WITH  THE  COX 

ROLLERS. 

Passing  by  for  the  present  the  direct  effect  of  the  process 
of  handling  on  the  leather,  in  this  chapter  will  be  considered 
merely  the  manipulation  of  the  stock,  with  reference  to  the 
amount  of  labor  required,  and  the  most  approved  methods 
for  doing  the  best  work  at  the  least  expense. 

In  no  department  of  the  tanners'  art  is  the  practice  of  dif- 
ferent establishments  more  varied  than  in  the  matter  of 
handling.  Patents  and  improvements,  almost  without  num- 
ber, have  from  time  to  time  been  pressed  upon  the  attention 
of  tanners,  and  the  methods  of  handling  are  to-day  as  varied 
almost  as  the  tanneries  are  numerous. 

Commencing  with  the  old  plan  of  "  hauling  up  "  by  hand, 
throwing  on  packs,  and  allowing  the  sides  to  press  and  drain 
for  a  portion  of  each  day — or  the  still  more  modern  practice 
of  "shifting"  over  from  one  vat  to  another — we  have  of  late 
years  adopted  mechanical  appliances  which  make  this  labor 
less  a  drudgery,  and  less  exacting  on  the  muscles  of  the  arms, 
back  and  legs.  The  most  generally  approved  methods  are  a 
"hand  reel"  and  the  "rocker  handler."  The  hand  reel  is  a 


THE   LEATHER   MANUFACTURE.  69 

revolving  skeleton  drum,  which  is  made  to  turn  on  the  top  of 
a  stand  or  frame  elevated  about  three  feet  above  the  top  of 
the  vats.  Both  wheel  and  frame  are  light  and  portable,  so 
that  two  men  can  easily  remove  them  from  one  location  to 
another,  over  the  t  ps  of  the  different  vats.  The  reel  is 
placed  on  the  alley-ways  between  the  vats  to  be  shifted,  and 
the  sides,  hides  or  skins  to  be  transferred,  being  tied  to- 
gether, are  drawn  over  from  one  vat  to  the  other  by  means 
of  this  revolving  drum.  One  man  is  required  to  turn  the 
crank  and  another  to  adjust  the  sides  or  hides  in  the  head 
vat.  By  actual  count  it  requires  four  minutes  for  two  men  to 
perfectly  transfer  150  sides  from  one  vat  to  another,  and  the 
labor  is  made  as  easy  as  the  old  method  is  fatiguing.  Two 
men  will  average  a  pack  every  eight  minutes  during  the  day, 
including  the  transfer  of  the  reel. 

The  "rocker"  handler  consists  of  a  frame  set  in  the  top  of 
the  vats,  constructed  of  wood.  This  frame  should  fill  the 
vit  within  two  inches  on  the  ends,  and  one  inch  on  the  sides, 
so  that  when  it  rocks  from  the  center  it  will  play  without 
touching.  It  should  be  made  of  two-inch  plank  and  the 
frame  should  be  of  stuff  2  by  6  inches  in  substance.  The 
end  pieces  should  be  of  hard  wood,  not  easily  split,  since 
they  must  bear  the  strain  of  the  whole  pack.  The  side  pieces 
may  be  of  pine  or  hemlock,  but  where  hard  wood  is  at  hand 
it  is  best  to  use  that  for  the  whole  frame.  The  center  of  the 
frame  rests  on  pivots  or  steps,  supported  by  uprights  from 
the  bottom  of  the  vat.  A  " stop"  at  each  end  of  the  vat  limits 
the  rocker  from  vibrating  up  and  down  more  than  about  eight 
inches.  It  is  not  intended  to  make  any  of  these  suggestions 
arbitrary  as  to  construction  or  working,  but  a  little  thought 
at  the  beginning  as  to  the  most  durable  construction  will  save 
iii'icli  repairing  in  the  course  of  years. 

The  sides  are  attached  alternately  by  the  head  and  tail  to 


70  THE   LEATHER  MANUFACTURE. 

the  cross  pieces,  backs  up  and  bellies  down,  by  means  of 
liard  wood  pins,  permanently  fastened  into  the  head  frame 
pieces.  Usually  one  end  is  fastened  directly  to  or  over  the 
pin,  and  the  other  by  an  adjustable  string,  which  may  be  not 
over  a  foot  long,  and  may,  by  a  permanent  slipping  noose,  be 
used  continuously. 

[In  the  illustrations  given  on  subsequent  pages  will  be 
found  good  representations  of  both  the  "hand  reel"  and 
il  rocker  handler,"  from  which  their  construction  and  the 
manner  of  operating  them  will  be  easily  understood.] 

This  "  rocker  handler  "  will,  also,  in  the  next  chapter,  be 
commended  over  any  or  all  other  methods  for  making  plump 
shoulders  and  offal,  as  well  as  for  general  economy. 

Besides  these  two  kinds  of  handlers  now  in  general  use 
(the  latter  in  the  lime  and  the  former  in  the  sweat  leather 
tanneries),  the  tanners  in  and  around  Baltimore,  Md.,  use  a 
lattice  drum  fully  immersed  in  the  liquor ;  from  the  outsido 
or  circumference  of  this  wheel  or  drum  the  sides  are  sus- 
pended, attached  alternately  by  the  head  and  tail.  One 
method  is  to  attach  the  leather  to  the  outside,  but  the  sides 
are  generally  suspended  on  the  inside  of  the  wheel  or  drum. 
In  the  first  case  the  sides  are  reeled  over  the  outside  of  the 
drum,  falling  in  folds,  much  as  the  top  of  an  .umbrella  comes 
together  when  put  down,  and  those  who  use  this  method 
claim  as  an  advantage  that  the  liquor  is  pressed  out  in  the 
process  of  turning  and  reeling  up  on  the  drum.  But,  as  an 
objection  to  both  of  these  plans,  it  may  be  said  that  they 
elongate  the  grain  transversely,  and  make  thin  backs  and 
thick  offal.  This  effect  is  more  noticeable  if  the  leather  is 
fully  tanned  in  this  manner,  without  being  taken  from  the 
original  vat  in  which  it  enters.  If  these  immersed  drum  reels 
were  used  only  as  handlers,  as  is  the  case  with  the  rocker, 
then  perhaps  the  effects  spoken  of  would  not  be  so  notice- 


THE   LEATHER  MANUFACTURE.  71 

able  ;  but  so  observable  are  these  defects  now,  that  there  is 
no  difficulty  in  distinguishing  leather  tanned  by  this  manip- 
ulation from  all  others,  by  the  long  grain  transversely  follow- 
ing the  line  of  the  back. 

The  liquors  are  pressed  around  to  strengthen  up  the  vats 
into  which  these  revolving  drums  are  used.  The  principle 
of  the  press  in  the  case  of  these  yard  vats  is  not  unlike  the 
press  of  the  leach  already  noticed  in  Chapter  YI.;  indeed, 
the  same  practice  brings  about  the  same  result.  Of  course 
no  agitation  of  the  liquor  is  permitted  while  the  press  is  in 
progress,  otherwise  the  liquor  would  mix  and  destroy  the 
principle  of  the  action. 

A  most  economical  and  efficient  method  of  facilitating  the 
raising  and  transfer  of  packs  laid  away  in  bark  is  effected  i  a 
the  following  manner :  A  light  frame  made  of  plank  is  laid 
on  the  top  of  the  liquor  before  commencing  to  lay  away  a 
pack.  At  the  outset  it  floats  on  the  liquor,  but  gradually 
sinks  as  the  sides  are  laid  on  and  "barked  away;"  when  the 
sides  are  all  in,  the  framework  is  at  the  bottom  of  the  pack. 

To  each  corner  of  this  frame  should  have  been  perma- 
nently fastened  a  half-inch  rope  as  long  as  the  vat  is  deep. 
The  loose  ends  of  these  ropes  may  float  on  an  attached  piece 
of  wood,  or  may  be  fastened  to  the  corner  of  the  vat.  When 
the  pack  is  to  be  raised,  the  men,  standing  at  each  end  of 
the  vat  with  one  of  these  ropes  in  each  hand,  together  raise 
the  whole  pack  to  the  surface,  and  when  so  raised  they  be- 
lay the  ropes  around  iron  bolts  or  wooden  pegs,  which  are 
temporarily  fastened  at  the  corners  of  the  vat.  After  they 
have  reached  down  and  removed  say  eight  or  ten  sides  from 
the  top  (all  that  they  could  readily  reach  without  the  aid  of  a 
hook),  then  they  again  raise  the  pack,  and  so  continue  until 
all  the  sides  are  thrown  upon  the  pile,  or  shifted  over  to  the 
next  vat;  but  usually  it  is  found  convenient  to  pile  the  pack 


72  THE   LEATHER  MANUFACTURE. 

up  on  the  adjoining  vat,  and  lay  away  in  the  same  vat  from 
which  the  sides  were  taken. 

The  philosophy  of  this  practice  consists  in  taking  advant- 
age of  the  law  of  specific  gravity.  A  side  of  leather  will 
weigh  less  ounces  under  water  than  pounds  out,  and  hence 
it  is  that  two  men  can  easily  lift  a  pack  while  fully  immersed 
in  water  or  liquor,  when  they  could  hardly  lift  ten  sides  if 
surrounded  by  air.  This  system  is  more  expeditious,  is  much 
easier  for  the  men,  and  withal  saves  all  opportunity  for  hook 
marks.  Will  harness  and  grain  leather  manufacturers  please 
take  notice  of  this  latter  advantage  ? 

There  is  still  another  form  of  handler  which,  by  way  of  des- 
ignation, may  be  called  the  tub  wheel  or  drum.  It  was  first 
used  at  Sparrowbush,  N.  Y.,  in  1860,  and  consists  of  a  large 
drum  fully  eight  feet  in  diameter,  and  the  width  of  the  vat. 
This  wheel  revolves  on  a  center  shaft  or  flange  and  gudgeon, 
resting  on  the  top  of  the  vat.  Nearly  one  half  of  this  wheel 
is  immersed  under  the  liquor  of  the  vat,  and  the  remainder 
is,  of  course,  out  of  the  liquor.  The  stock  is  thrown  in  at  a 
side  trap  door,  and  revolved  inside  this  wheel  until  colored  or 
ready  to  go  into  the  layaways.  Projecting  wooden  pins  from 
the  inside  surface  separate  and  carry  around  the  stock.  A 
more  recent  improvement  on  this  wheel  is  to  divide  it  off 
into  four  segments  or  sections,  and  thus  make  the  compart- 
ments smaller.  It  is  claimed  for  this  improvement  that  the 
wheel  turns  easier,  as  a  portion  of  the  contents  is  always 
held  near  the  center,  and  only  goes  to  the  circumference  a 
portion  at  a  time.  Besides,  a  Swiss  calfskin  tanner  told  the 
writer  that  it  was  within  his  experience  that  the  large  wheel 
without  partitions  was  too  severe  on  green  stock.  He  was 
probably  right,  for  such  violent  action  is  apt  to  "purge" 
stock  when  it  is  green  and  the  liquors  are  weak,  as  they  al- 
ways must  be  in  the  earlier  process. 


THE   LEATHER   MANUFACTURE.  73 

The  hanging  of  sides,  hides  or  skins  over  cross  sticks  held 
tip  by  lateral  supports  in  the  vat,  and  the  agitation  of  the 
liquor  by  plunging,  is  a  most  economical  method  of  hand- 
ling, and  one  that  should  be  resorted  to  by  all  tanners  who 
cannot  conveniently  adopt  the  rockers.  The  "  strengthening 
up"  may  be  effected  by  drawing  off  say  one-quarter  or  one- 
third  of  the  contents  of  the  vat,  and  replacing  by  stronger 
liquor.  The  gentle  agitation  of  the  fiber  and  the  exposure  of 
the  full  surface  of  both  grain  and  flesh  to  the  action  of  liquor 
is  essential  to  a  proper  handling  process,  and  so  long  as  this 
can  be  effected,  no  matter  whether  by  manual  or  mechanical 
methods,  it  is  all  the  same  in  effect. 

The  process  which  has  for  so  long  a  time  been  improperly 
attributed  to  Mr.  England,  and  known  as  the  "England 
wheel"  method,  has  very  general  acceptance  by  many  light 
leather  tanners.  In  this  method  of  handling  the  wheel  re- 
volves on  the  top  of  the  vat,  and  is  constructed  in  skeleton 
form,  with  buckets  or  paddles,  which,  when  turned,  dip  about 
six  inches  in  the  liquor,  causing  a  thorough  and  constant  agi- 
tation of  the  contents  of  the  vat.  If  the  vat  is  square  in  the 
bottom  there  will  be  a  great  agitation,  and  it  will  answer  im- 
perfectly the  purpose,  but  to  make  the  liquor  and  the  stock 
contained  in  the  vat  revolve  at  the  same  time  with  the  greatest 
facility,  the  bottom  of  the  vat  should  be  circular,  but  not  lat- 
ticed, as  was  contemplated  by  the  patent  of  Mr.  England. 

This  description  of  a  circular-bottomed  vat  with  a  revolving 
wheel  in  the  top  had  its  origin  in  the  city  of  Brooklyn  about 
the  year  1840  ;  but  circulating  or  handling  vats,  in  a  modified 
form,  were  well  known  in  Germany  long  before  they  were  in- 
troduced here.  For  the  coloring  of  sheep,  calf,  kip,  light 
upper  or  splits,  this  wheel  and  circular-bottomed  vat  is  most 
serviceable,  but  when  applied  to  the  after  process  of  tanning, 
as  has  been  attempted,  especially  in  heavy  leathers,  must  al- 


74  THE  LEATHER   MANUFACTURE. 

ways  result  in  failure,  according  to  the  experience  of  the 
writer. 

Mechanical  power  should  always  be  introduced  into  the 
handling  yard.  Ah1  the  mechanical  appliances  which  have 
been  mentioned  are  capable  of  being  operated  by  shafting, 
pulleys  and  belting.  The  "rockers"  and  " skeleton  drums," 
particularly,  should  be  driven  by  power,  which  may  be  ac- 
complished by  allowing  a  shaft  to  run  overhead  and  between 
each  tier  of  vats.  An  "eccentric"  or  "crank"  motion  can 
easily  be  geared  from  a  shaft,  as  all  mechanics  understand. 

The  writer  has  not  called  attention  to  several  attempts  to 
raise  whole  packs,  both  in  the  handlers  and  also  in  the  lay- 
away  s,  by  mechanical  power,  because  they  are  generally  ex- 
pensive and  ineffectual  methods  of  handling. 

Perhaps  this  list  of  handlers  would  not  be  complete  with- 
out including  the  patented  rollers  of  a  Mr.  Cox,  of  London, 
which  were  brought  to  this  country  about  the  year  1840,  and 
were  adopted  only  in  one  or,  at  most,  two  yards,  but,  as  they 
were  in  quite  extensive  use  in  some  portions  of  Great  Britain, 
they  deserve  this  mention.  The  rollers  are  made  of  wood, 
and  are  covered  with  cloth  or  matting;  two  rollers,  about 
two  feet  in  diameter  each,  are  made  to  revolve  with  their 
surfaces  so  close  together  as  to  draw  the  side  through  and 
squeeze  out  the  spent  liquor,  which,  according  to  the  theory 
of  this  patentee,  has  deposited  its  tannin,  and  should  be  dis- 
placed to  give  opportunity  for  new  and  freshly  charged  ooze, 
to  come  in  contact  with  the  gelatine  of  the  hide.  The  sides 
or  butts  are  tied  together  in  such  way  as  to  make  a  contin- 
uous belt,  and  by  means  of  these  compressing  rollers  are 
drawn  from  one  vat  and  dropped  over  into  the  next. 

The  effect  of  this  frequent  compressing  of  the  fiber  is  to 
make  the  leather  thin  and  hard.  The  writer  has  seen  some 
very  heavy  weighing  leather  made  by  these  rollers,  but  as  the 


THE   LEATHER  MANUFACTURE.  75 

system  contemplated  and  used  much  stronger  liquor  than  it 
was  usual  for  our  tanners  to  employ  at  that  time,  to  this  cause 
was  attributed  the  wonderful  resulting  gain.  In  the  first  ex- 
periment with  these  rollers  at  one  of  the  tanneries  in  this 
country  194  pounds  of  leather  were  made  from  100  pounds  of 
dry  Buenos  A\  res  hides,  but  the  rollers  were  so  expensive 
that  they  have  long  since  gone  into  disuse  here,  and  meas- 
urably so  in  England ;  yet  it  must  be  confessed  that  for  butts, 
bends  and  trimmed  leather,  it  is  much  better  suited  than  to 
our  sides,  and  to  supply  a  demand  for  firm  and  even  hard 
leather,  as  is  required  in  Great  Britain,  these  rollers  may 
serve  a  useful  purpose. 

So  long  ago  as  the  year  1842  the  writer  saw  at  Woburn, 
Mass.,  a  process  of  handling  upper  leather  on  frames,  immersed 
in  the  vats,  which  at  that  early  day  presented  a  foreshadowing 
of  the  more  modern  and  better  process  of  rocking  the  hand- 
lers. But  even  yet  the  stationary  sticks  or  frames  are  in  use 
by  pebble  and  grain  leather  tanners  in  several  large  tanneries. 
This  successful  practice  only  demonstrates  what  the  writer 
has  repeatedly  had  occasion  to  say,  viz.,  any  method  by 
which  the  fiber  is  gently  agitated  and  tho  whole  surface  ex- 
posed to  the  liquors  will  answer  the  purpose  contemplated. 


CHAPTEE    VIII. 
HANDLING    AND    PLUMPING. 

THE  USE  OF  VEGETABLE  AND  MINERAL   ACIDS THE   EARLY   USE    OF  VITRIOL 

BY     AMERICAN    TANNERS CONSIDERATIONS    AFFECTING    THE    AMOUNT 

WHICH    MAY    BE    USED ITS    EFFECT    ON    LIMED    AND   SWEAT  STOCK 

STRENGTH  AND  AGE  OF  LIQUORS  TO  BE  USED  IN  THE  HANDLERS DIF- 
FERENCES IN  THE  HANDLING  AND  PLUMPING  OF  SOLE  AND  UPPER  LEA- 
THER. 

Tlie  treatment  of  sole  leather  is  so  different  from  that  of 
upper,  harness,  etc.,  in  the  preliminary  or  handling  process, 
that  the  work  on  these  two  classes  of  stock  will  be  consid- 
ered separately. 

It  has  become  of  late  years  quite  universal  to  make  a  dis- 
tinction between  "acid"  and  "non-acid"  treatment  in  pre- 
paring hides  to  be  tanned  into  sole  leather.  These  terms, 
although  in  common  use,  do  not  convey  an  accurate  idea  of 
the  differences  in  the  process.  No  sole  leather  is  prepared 
for  the  yard  without  the  use  of  acid  of  some  kind,  but  what 
is  meant  by  the  term  "non-acid"  is,  that  only  gallic  acid 
coming  from  bark  liquor  is  used  in  the  one  case,  and  in  the 
other  sulphuric  acid  or  vitriol  is  employed.  This  employment 
of  vitriol  as  a  means  of  plumping  the  fiber  of  the  hide  is  of  quite 
recent  date  in  this  country.  In  Great  Britain  the  distinction 
has  been  maintained  for  a  long  time  between  "vitriol"  butts 
and  bends  and  those  that  are  not  raised  by  this  process.  As 
early  as  1853  the  writer  commenced  the  use  of  vitriol  in  the 


THE  LEATHER  MANUFACTURE.  77 

preparation  of  "union  crop"  .leather.  But  this  was  on 
limed  stock,  and  in  very  moderate  quantities.  The  mineral 
acid  was  used  quite  as  much  to  counteract  and  neutralize  the 
lime  as  to  plump  the  fiber.  When  used  to  this  limited  extent 
the  "buff"  was  not  injured,  the  grain  was  plumped,  and  the 
whole  structure  of  the  hide  slightly  swelled.  But  from  this 
small  and  cautious  beginning  the  use  of  vitriol  extended  until 
the  sweat  leather  tanners  took  it  up,  and  from  about  1860  to 
the  present  time  it  has  come  into  general  use. 

If  this  practice  had  been  intelligently  and  openly  intro- 
duced, far  less  damage  would  have  resulted ;  but  each  tanner, 
depending  upon  his  own  judgment,  and,  it  must  be  confessed, 
on  very  limited  information,  has  gone  on  blunderiDg,  all  the 
time  thinking  himself  much  wiser  and  more  skillful  than  his 
neighbor,  until  vitriol-raised  leather  has  come  to  receive  the 
condemnation  of  all  of  our  best  manufacturers.  Certainly  it 
is  discredited  by  all  who  have  regard  to  the  appearance  of 
the  bottoms  of  their  boots  and  shoes. 

For  several  years  after  the  first  introduction  of  the  new 
practice  the  fact  of  the  use  of  vitriol  was  kept  a  secret,  and 
was  not  exposed  until  the  general  quality  of  our  sweat  leather 
'had  deteriorated  to  such  an  extent  as  to  cause  alarm. 
Now  the  proper  use  of  this  acid  is  better  understood,  and  the 
early  abuses  in  its  application  are  measurably  avoided ;  but 
even  to  this  day  many  otherwise  good  tannages  are  injured 
by  the  improper  use  of  vitriol  in  the  handlers.  In  this,  as  in 
all  other  innovations,  there  should  be  more  frankness  among 
the  tanning  fraternity ;  its  members  should  learn  that  ignor- 
ance and  bad  workmanship  reflect  finally  as  much  on  the  in- 
nocent as  on  those  who  are  more  directly  responsible.  A 
tanner  who  makes  poor  leather,  particularly  if  the  defects 
are  latent  and  not  at  once  discernible,  unfavorably  influences 
the  whole  trade. 


78  THE  LEATHEE  MANUFACTURE. 

The  writer  would  gladly  impart  such  information  in  regard 
to  the  proper  and  permissible  use  of  vitriol  as  would  help 
tanners  to  avoid  the  defects  complained  of,  but  the  circum- 
stances under  which  this  acid  is  employed  are  so  varied  that 
any  general  formula  or  direction  for  its  use  would  be  almost 
certain  to  mislead  some  of  those  who  might  wish  to  be  guided 
thereby.  Hides  are  not  all  of  the  same  specific  nature ;  some 
will  bear  more  acid  than  others.  Thick  hides  will  bear  more 
than  thin  ones  ;  steers  more  than  cows ;  the  butts  more  than 
the  bellies  of  the  same  hide.  The  consequence  is  that  when 
our  American  sweat  leather  tanners  use  vitriol  on  hides 
worked  in  without  proper  classification,  and  without  trim- 
ming, they  are  apt  to  overdo  the  thin  sides  or  thin  portions 
of  the  thick  ones.  There  is  no  way  to  avoid  this  difficulty 
without  taking  care  only  to  strike  the  thin  portions  fairly 
through  and  then  stop,  leaving  the  butt  only  partially  im- 
pregnated. 

In  regard  to  the  experience  and  practice  of  our  sweat  lea- 
ther tanners  in  tho  use  of  vitriol — some  color  their  sides  be- 
fore they  introduce  them  to  the  acid ;  others  use  the  acid  first 
and  color  last,  while  still  others,  and  probably  the  majority, 
use  both  agents  at  the  same  time — they  color  while  they 
plump — i.  e.,  they  use  the  acid  in  the  coloring  handlers,  and 
strengthen  up  the  handler  as  each  new  pack  goes  in,  with 
new,  sweet,  highly  colored  liquor  and  vitriol. 

How  much  vitriol  may  be  used  with  each  pack?  This 
question  is  often  asked,  but  can  never  be  definitely  answered 
without  a  knowledge  of  the  hides,  and  of  other  circum- 
stances. It  must  depend  upon  how  much  the  previous 
pack  has  taken  up;  how  strong  the  acid  is;  how  heavy 
the  sides  are ;  how  fully  the  leather  is  allowed  to  carry  off 
the  acid,  etc.  There  will  be  no  difficulty  experienced  if  tan- 
ners will  regard  vitriol  plumping  as  a  tawing  process.  If  they 


THE  LEATHER  MANUFACTURE.  79 

r/ill  cut  the  thin  portions  of  the  sides,  and  examine  in  a  strong 
light,  they  will  notice  just  the  extent  to  which  the  acid  has 
penetrated ;  the  progress  is  as  clearly  defined,  although  not 
quite  so  plainly  marked,  as  if  the  tan  liquor  itself  had  been 
present. 

Yitriol  preserves  the  hide,  and  holds,  when  combined  with 
salt,  the  gelatine  from  decay.  All  the  green  sheepskin  pelts 
tli at  come  from  England  to  this  country  in  casks  are  pre- 
served by  this  process,  and  may  be  so  held  without  damage 
for  years.  "When  these  skins  come,  however,  to  be  tanned, 
the  acid  must  be  neutralized  before  they  go  into  the  liquor, 
or  while  in  the  liquor,  otherwise  a  result  is  produced  just  such 
as  we  see  in  much  of  our  acid  sole  leather.  A  sheepskin 
tanned  without  neutralizing  the  acid  will  swell  to  more  than 
double  its  wonted  thickness,  and  will  tear  as  easily  as  brown 
paper  of  the  same  substance,  while  the  whole  structure  as- 
sumes a  dark  brown  hue,  which  grows  darker  as  it  is  exposed 
to  the  air.  From  this  fact  tanners  may  take  a  hint,  as  the 
writer  has  done.  Indeed,  from  some  early  experience  in  tan- 
ning what  are  termed  "salted"  sheepskins,  much  of  my  early 
knowledge  of  the  use  of  vitriol  was  obtained. 

Vitriol  distends  and  injures  the  fiber,  and  if  not  re- 
moved from  the  grain  will  deposit  immediately  underneath  it 
a  dark  brown  strata,  which  is  most  objectionable  to  manufac- 
turers who  use  buffing  wheels  instead  of  hand  labor  in  re- 
moving the  grain  on  the  soles  of  boots  and  shoes. 

In  my  judgment,  vitriol  should  never  be  used  to  raise 
purely  sweat  stock.  For  hides  prepared  with  lime  we  all 
know  that  vitriol  to  a  limited  extent  may  be  used  without 
material  damage.  What,  then,  is  to  be  done?  All  sides  as 
they  come  from  the  sweats  should  be  thrown  into  a  lime,  and 
there  handled  until  they  fairly  begin  lo  feel  its  effects,  say, 
ordinarily,  about  six  or  eight  hours.  The  lime  will,  in  this 


80  THE  LEATHER  MANUFACTURE. 

time,  sufficiently  penetrate  the  surfaces  to  neutralize  the  acid 
when  the  sides  reach  the  handlers.  Thus  treated  the  dark 
strata  will  be  either  entirely  removed,  or  so  far  modified  as 
to  be  less  objectionable,  depending  on  the  strength  of  the 
lime  and  vitriol  used  and  their  relative  proportions. 

It  should  be  remembered  that  sole  leather  raised  with 
gallic  acid  (if  the  acid  be  strong)  will  leave  a  modified  dark 
strata,  but  this  is  controllable  by  other  acids,  which  the  boot 
and  shoe  manufacturers  employ  in  "  cleaning  up  their  bot- 
toms." No  counteracting  agent  has  yet  been  found,  however, 
for  the  vitriol  stain,  and  the  exposure  to  the  atmosphere  of 
leather  thus  affected  increases  its  unsightly  appearance. 

The  German-tanned  "warm-sweat"  sole  leather  has  the 
difficulty  here  complained  of  to  a  more  marked  and  objection- 
able extent  even  than  our  own  tannages ;  but  as  the  consumers 
there  care  less  for  the  buff  than  we  do,  this  defect  seems  to  be 
disregarded.  They  use  vitriol  or  acid  liquors  even  to  a  greater 
degree  than  we  do,  and  to  such  an  extent  indeed  that  most  of 
their  sweat  sole  leather  will  crack  and  even  break  by  close 
folding.  Consumers  of  leather  in  Continental  Europe,  hav- 
ing been  accustomed  to  this  defect  in  their  own  home  supply, 
make  less  objection  to  it  in  us  than  do  the  manufacturers  of 
Great  Britain.  The  tanners  of  Great  Britain  do  not  sweat, 
either  by  "cold"  or  "warm"  process,  and  hence  they  use 
vitriol  and  lime  jointly,  with  less  damaging  effect. 

It  is  proper  here  to  say  that  in  France,  Germany  and  Swit- 
zerland women's  sole  leather  and  .all  the  light  leathers  are 
limed,  as  in  Great  Britain,  and  this  "cracking"  and  "old 
hatty"  appearance  of  the  fiber  is  confined  to  the  sweat  vitriol 
and  acid  raised  sole  leather,  which  are  greatly  inferior  to 
their  other  tannages. 

Vitriol-raised  leather,  when  treated  in  the  after  process 
with  weak  liquors,  produces  a  m6st  unsatisfactory  result. 


THE  LEATHER  MANUFACTURE,  81 

Tlie  grain  is  poor,  the  fiber  coarse  and  hatty.  No  attempt  is 
here  made  to  solve  the  mooted  question  whether  vitriol  does 
not  destroy  the  tannin.  It  is  conceded  that  it  will  plump  and 
hold  the  fiber,  and  will  facilitate  the  tanning,  but  whether 
these  advantages,  in  an  economical  point  of  view,  are  not 
more  than  overbalanced  by  its  distinctive  action  on  both  fiber 
and  the  tannin,  must  be  left  for  future  experience  to  de- 
termine. 

In  closing  the  suggestions  on  this  point  the  writer  would 
like  to  say  that  great  care  should  be  exercised  in  handling 
while  in  the  vitriol  vat.  If  the  acid  is  allowed  to  settle  down 
on  tlie  grain,  stains  will  result  which  will  cause  a  clouded  ap- 
pearance that  will  remain  to  the  end  of  the  tanning  process. 
My  own  judgment  is  that  it  will  always  be  serviceable  to  hang 
the  sides  on  cross  sticks  and  plunge  as  the  most  certain 
method  of  distributing  the  effects  of  the  acid  uniformly.  In 
adding  vitriol  to  the  pack,  be  sure  to  put  it  in  before  the 
sides  go  in,  and  plunge  thoroughly,  otherwise  the  acid  will 
drop  down  and  discolor  the  grain.  The  specific  gravity  of 
vitriol  being  much  heavier  than  that  of  tan  liquor,  its  tend- 
ency is  to  settle,  and  unless  great  care  is  taken  it  will  so 
settle  and  mottle  the  grain  of  the  pack. 

In  preparing  hides  for  sole  leather  by  the  lining  process, 
if  only  so  much  lime  is  allowed  to  permeate  the  fibar  as  to 
enable  the  tanner  to  remove  the  hair,  as  has  been  already 
indicated,  distinct  bating  is  unnecessary.  If  the  hide  is 
filled  and  swelled  with  lime,  the  treatment  should  be  such 
as  to  remove  such  excess  of  lime  before  the  sides  come  to  the 
handler.  But,  usually,  if  the  sides  are  wheeled  in  warm 
water  for  ten  or  fifteen  minutes,  they  will  be  sufficiently 
cleansed  to  enter  the  handler. 

The  first  handler  liquor  should  be  the  oldest  and  most 
worthless  liquor  in  the  yard,  so  worthless  that  after  handling 

6 


82  THE  LEATHER  MANUFACTURE. 

the  green  pack  in  it  for  a  few  hours  it  can  be  run  off  in  the 
stream  or  sent  again  to  the  back  leach.* 

The  pack,  after  being  thus  cleansed,  so  far  as  this  old  spent 
liquor  will  do  so,  takes  its  place  in  the  order  of  succession  in 
the  handlers.  If,  as  is  assumed,  the  rocker  system  of  hand- 
ling is  observed,  then  it  will  take  the  place  of  the  pack  which 
has  just  gone  to  the  layaways,  and  a  liquor  is  prepared 
specially  by  pumping  the  strong  liquor  found  in  the  vat  over 
on  the  next  pack,  and  so  on  around  until  the  weakest  liquor 
is  placed  on  the  new  incoming  pack ;  care  should  be  observed 
to  feed  each  pack  with  an  increasingly  strong  liquor,  not,  as 
too  many  practice,  once  in  each  day,  but  at  least  twice. 

Far  more  damage  is  done  by  feeding  too  slow  than  too 
fast ;  so  long  as  the  old  liquors  from  the  layaways  are  used 
there  need  be  no  fear  of  either  feeding  the  packs  too  fast  or 
too  frequently,  only  let  them  be  fed  in  their  order  of  entrance. 

Of  course,  as  many  packs  should  go  out  as  come  into  the 
handlers  daily.  It  will  be  found  profitable  to  keep  each  pack 
from  ten  to  twelve  days  in  the  handling  rockers,  or  in  any 
other  method  of  handling  that  may  be  adopted.  This  time 
will  suffice  to  overcome  all  the  effects  of  the  lime,  fairly 
plump  the  sides,  and  set  them  well  on  their  way  toward  the 
after  tanning  process. 

As  a  last  parting  word  on  this  subject  the  writer  would  urge 
tanners  to  put  away  from  their  minds  the  fear  so  often  ex- 
pressed that  liquors  may  be  too  strong  to  start  with.  If  eight 
or  ten  packs  are  in  the  handlers,  commencing  with  the  head 

*  Just  here  the  writer  would  say  that,  whether  this  old  liquor  should  go  again 
to  the  back  leach  or  off  in  the  stream  Avill  dep3nel  very  much  on  the  manner  of 
us'ng  tlic:  liquors.  If,  as  in  the  true  system  of  using  the  press  leach,  no  liquor  is 
allowc.l  to  go  back  until  expense:!,  then  the  dirty  water  (for  it  is  little  more), 
without  acid  or  tannin,  which  washes  anl  cleanses  each  new  pack  which  comes  to 
the  han  Hers,  should  be  discarded  ;  but  if  there  should  remain  either  gallic  acid  or 
tannin  in  the  liquor,  then  it  should  certainly  go  to  the  back  leach.  Without  exer- 
cising some  discretion  in  this  regard  valuable  qualities  may  be  thrown  away. 


THE  LEATHEE  MANUFACTURE.  83 

pack  and  running  down  to  the  last  one,  the  best  and  strong- 
est of  the  discarded  layaway  liquors  may  be  used  with 
safety.  These  liquors  will  always  contain  acid  enough  to 
prevent  the  "puckering"  or  "  binding"  of  the  grain.  Liquors 
weighing  by  the  barkometer  16°  are  none  too  strong  for  the 
head  handler.  So  large  a  proportion  of  this  weight  will  be 
acid  that  they  may  safely  be  trusted  to  work  no  harm. 

The  treatment  of  the  lighter  tannages,  such  as  upper  and 
harness  leather,  in  the  handlers,  is  far  different  from  that  of 
the  heavy  sole  leather  tannage,  just  considered.  These  lea- 
thers are  sold  by  the  side  or  foot,  or  should  be,  as  no  tanner 
can  afford  to  treat  his. stock  as  such  goods  should  be  treated, 
and  then  sell  it  by  weight. 

After  the  lime  has  been  thoroughly  removed  by  a  bate  of 
hen  manure,  or  wheat  bran,  or  some  other  depleting  process, 
the  stock  enters  the  handler,  in  the  first  instance  just  as  tha 
sole  leather  did,  but  instead  of  taking  a  course  of  old,  sour, 
strong  liquors,  it  is  only  retained  long  enough  in  the  acid 
liquors  to  "brighten"  and  clear  the  grain,  and  then  weak, 
sweet  liquors  should  be  fed  to  the  packs,  just  in  the  order 
in  which  they  come  from  the  leaches.  These  liquors  should 
go  back  to  the  leaches  very  frequently,  to  be  "  sweetened  " 
and  "  strengthened  "  up.  Fresh  sweet  liquors  standing  from 
10°  to  12°  should  be  as  strong  'as  is  ever  permitted  in  the 
handlers.  The  "  rockers  "  should  be  used,  however,  to  plump 
and  handle  even  upper,  harness  and  calf,  for,  although  the 
sweet  liquor  will  prevent  that  extreme  plumpness  so  desir- 
able in  the  heavier  tannages,  a  close,  round  grain  will  be 
formed,  and  a  degree  of  fineness  and  plumpness  of  the 
shoulders  and  offal  will  be  secured  not  attainable  by  the 
usual  manual  handling  process. 


CHAPTEK    IX. 
LAYING   AWAY. 

TIME  REQUIRED  AND  STRENGTH    OF  LIQUOR  WHICH  SHOULD  BE  EMPLOYED—- 
TANKING IN  THE  HANDLERS  VS.  LAYING  AWAY EUROPEAN  METHODS 

"  BLACK  ROT  "   AND  WHITE   SPOTS THEIR  CAUSES   AND  THE   REMEDIES 

SHOULD   HIDES  BE   LAID   AWAY   GRAIN   UP    OR   FLESH  UP  ? MAKING 

WEIGHT  IN  THE  LAST  LAYER. 

Proceeding  in  the  order  of  the  successive  processes  of  tan- 
ning, we  find  our  pack  coming  from  the  handlers  not  only 
well  "plumped"  and  uniformly  "colored,"  but  fairly  "leath- 
ered." The  stock  has  taken  upon  itself  "  substance,"  and  a 
reasonable  degree  of  firmness.  Supposing  that  four  layers 
will  now  carry  out  our  tanning  and  completely  fill  the  fiber, 
we  shall  assume  that  the  remaining  work  will  be  divided  into 
the  following  periods  of  time,  during  which  four  successive 
layers  of  bark  will  be  given  each  pack.  To  the  first  layer  we 
will  give  ten  days,  to  the  second  fifteen  days,  to  the  third 
twenty  days,  and  to  the  fourth  thirty  days,  making  in  all 
seventy-five  days.  But  it  must  be  evident  that  leather  differ- 
ing in  substance  and  weight  will  considerably  vary  in  its 
requirement  of  time  ;  and  then,  too,  much  will  depend  upon 
the  season  of  the  year,  the  strength  of  liquors  applied,  and 
other  circumstances.  If  we  commence  with  a  liquor  of 
16°  degrees  strength  with  the  first  layer,  and  end  with  30°  on 
the  fourth  layer,  seventy-five  days  will  be  found  ample  time 
to  tan  the  heaviest  sole  leather. 

The  writer  tried  an  experiment  on  one  pack  of  slaughtei 


THE  LEATHER  MANUFACTURE.  85 

hides,  to  test  the  actual  time  necessary  to  tan  good  middle 
and  overweight  leather,  averaging  say  20  pounds  per  side. 
This  experiment,  made  under  his  own  daily  observation, 
enables  him  to  speak  with  great  confidence  of  the  result. 
The  hides  were  bought  of  the  Batchers'  Association  of  the 
City  of  New  York,  and  weighed  70  pounds  each,  trimmed 
and  cured.  On  3  week  was  consumed  in  their  preparation  for 
the  bark.  They  were  colored  and  handled  for  three  da}^s  in 
an  old  sour  liquor  from  the  first  layers,  when  they  were  put 
into  a  liquor  of  20  degrees  strength  and  handled  daily, 
"shifting"  from  one  vat  to  another  each  day,  and  receiving 
just  enough  added  strength  to  keep  the  liquor  at  20  degrees. 
At  no  time  was  the  liquor  over  22  degrees  or  under  18  degrees. 
IL.  sixty-one  days  from  the  time  the  sides  came  l^to  the  hand- 
lers they  were  taken  out  not  only  fairly  "  struck,"  but  well 
tanned.  The  color  was  "fairly  good,"  although  not  as  bright 
as  other  packs  which  hacTbeen  laid  away  in  the  usual  manner, 
and  had  taken  fifteen  to  twenty  days  more  time.  The  con- 
clusions drawn  from  that  experiment  were  as  follows : 

1.  Well  cured  New  York  City  hides  will  make  65  pounds 
of  leather  for  every  100  pounds  of  green  cured  and  trimmed 
hides. 

2.  Sixty  days  in   the  actual  process  of  tanning,  handling 
once  each  day  in  suitable  liquors,  will  tan  the  ordinary  middle 
and  overweights  sole  leather. 

3.  About  one-third  more  time  is  required  if  the  leather  is 
tanned  by  being  laid  away  in  the  usual  manner. 

4.  The  color  is  both  lighter  and  more  uniform  when  laid 
away  than  when  handled.     Besides,  the  tendency  of  the  sides 
to  bag  is  far  less  when  tanned  in  the  usual  way,  by  laying 
away  in  bark. 

This  experiment,  if  read  by  a  German,  Swiss,  French  or 
Austrian  taniier,  will  be  regarded  as  extraordinary,  but  an 


86  THE   LEATHER   MANUFACTURE. 

account  of  it  is  given  here,  not  because  it  is  exceptional  in 
this  country — for  many  better  results  have  been  attained — 
but  for  the  purpose  of  bringing  into  contrast  our  methods  of 
tanning  as  compared  with  those  of  the  Continent  of  Europe, 
for  in  all  statements  affecting  results  the  writer  must  be 
understood  as  drawing  a  clear  distinction  between  the  pro- 
cesses in  Great  Britain  and  those  of  the  Continent. 

It  is  not  claimed  that  these  results  are  practically  secured 
in  all  instances,  or  even  in  a  majority  of  cases  in  this  coun- 
try, for  the  causes  of  detention  which  go  to  make  the  aver- 
age time  and  results  are  but  too  well  known.  These  causes 
of  delay  will  be  considered  in  their  appropriate  place,  but 
theoretically  our  system  accomplishes  all  that  is  here  claimed. 

As  possibly  these  statements  may  be  read  by  tanners  over 
the  sea,  for  their  information,  as  well  as  for  the  instruction 
of  our  own  tanners,  it  may  be  said  that  our  universal  custom 
of  leaching  new  bark  and  using  the  decoction  obtained  for  our 
tanning  agent,  is  not  practiced  to  any  extent  by  tanners  in 
Continental  Europe.  They  color  their  green  packs  in  hand- 
lers made  from  the  old  sour  liquors,  which  are  pumped  from 
the  layaways,  adding  (as  is  the  custom  of  some)  a  few  bas- 
kets of  "  spruce  "  bark.  The  hides,  in  small  yards  that  are 
run -without  power,  are  "poled"  in  the  vat  every  hour,  and 
onoe  or 'twice  each  day  the  stock  is  handled  up.  But  while 
yet  quite  "green"  and  "pulpy  "  the  packs  are  laid  away  in 
outdoor  round  tubs  or  vats,  from  eight  to  twelve  feet  deep, 
and  from  six  to  ten  feet  in  diameter. 

The  first  layer  is  made  of  old,  partially-spent  tan,  laid  fully 
one  inch  thick  on  either  side  of  a  hid-i  or  skin,  and  well 
stamped  down.  "When  the  vat  is  finally  filled  with  these 
alternate  layers  of  bark  and  green  pelts,  water  is  run  in  to  fill 
the  interstices.  The  acid  of  the  bark  preserves  the  gelatine, 
and  at  the  same'  time  neutralizes  any  lime  which  may  liave 


THE   LEATHEB   MANUFACTURE.  37 

been  left  from  the  handlers.  After  twenty  or  thirty  d 
time  this  stock  is  raised,  the  bark  "skimmed  out,"  and  tlie 
pack  relaid.  To  the  old  a  portion  of  new  bark  is  added, 
and  at  each  subsequent  "shift"  or  "turn"  of  the  pack 
more  new  bark  is  added,  all  the  time  holding  the  old  acid 
liquor  which  has  accumulated. 

The  writer  was  informed  that  in  most  instances  from 
sixteen  to  twenty  months  are  occupied  in  these  layers  before 
the  leather  is  finally  declared  tanned,  and  the  statement  may 
be  fully  credited,  for.  in  no  instance,  among  the  numerous 
tanneries  visited,  did  he  see  any  attempt  to  leach  new  bark ; 
such  leaching  as  was  attempted  was  confined  to  the  old,  spent 
bark,  that  had  been  literally  worn  out  by  frequent  handling. 
This  process  is  slightly  varied  with  calf  and  upper  in  the 
handlers  and  layaways,  but  substantially  the  same  system  is 
followed  out  in  ah1  their  tanning.  Perhaps,  in  justice  to  a 
few  large  calfskin  tanners — notably  so  in  the  case  of  M. 
Mercier,  at  Lausanne,  Switzerland — it  should  be  said  that 
much  more  vigor  and  a  greatly  improved  system  was  em- 
ployed. This  will  be  more  fully  mentioned  in  the  chapters 
on  calfskin  tannages,  in  another  place. 

The  writer  hesitates  to  state  the  methods  employed  in 
Great  Britain,  for  the  tanning  agents  there  used  are  so  en- 
tirely different  from  our  own  that  comparisons  are  impossible, 
and  might,  if  given,  be  misunderstood.  They  use  decoctions 
quite  as  strong,  in  fact,  as  we  do,  and  much  stronger,  meas- 
ured by  the  test  of  the  barkometer,  while  the  time  in  which 
they  tan  is  very  nearly  or  quite  equal  to  tljat  made  by  our 
best  tanners.  If  they  take  longer  (as  many  of  them  do),  as 
much  even  as  ten  months,  it  is  on  heavy  South  American 
hides,  made  into  butts  and  bends  that  are  very  stout  in  sub- 
stance and  extremely  fine  in  texture.  But  native  sole  leather 
hides,  also  upper  and  kip  leather,  from  both  native  and  foreign 


88  THE  LEATHER  MANUFACTURE. 

hides,  are  "put  through"  quite  within  our  best  time,  and  in 
the  most  artistic  way.  American  tanners  can  learn  much 
from  the  economies  practiced  and  results  produced  by  the 
tanners  of  Great  Britain,  for  they  do  manage  to  make  ex- 
ceedingly good  leather  from  very  small  quantities  of  tan- 
ning material,  whether  native  or  foreign. 

To  return  from  this  necessary  digression  our  methods  of 
laying  away  will  now  be  given  with  more  minuteness.  More 
than  forty  years  has  passed  since  the  "kiffing"  away  process 
was  given  up,  and  leaching  and  bark  liquors  introduced  in  its 
-stead.  Few  men  are  old  enough  to  remember  when  at  Salem, 
Danvers  and  Cummington,  Mass.,  water  was  used  instead  of 
liquor  in  the  layaways  for  sole  leather  tanning.  At  present, 
the  bark  liquor  used  in  the  layaways  is  depended  upon  to  do 
the  tanning,  and  not  the  interlying  bark  at  all. 

The  general  usage  now  is  to  run  the  strongest  and  newest 
liquor  direct  from  the  leaches  upon  the  head  packs  of  the 
last  layer.  These  liquors  should  weigh  by  the  barkometer 
fully  30  degrees  of  strength.  After  30  days'  use  they  will  be 
reduced  to  24  degrees.  A  portion  of  this  indicated  strength 
is  acid.  Twenty  days'  further  use  on  the  third  layer  will 
reduce  the  strength  to  18  degrees,  and  thus  down  step  by 
step  until  a  large  portion  of  the  strength  will  be  acid  and  not 
tannin,  when  the  liquors  will  be  put  on  the  first  layaways, 
or  may  be  run  into  the  handlers  and  fully  exhausted. 

This  is  not,  it  is  true,  an  invariable  custom,  for  too  few  of 
our  tanners  have  anything  that  may  be  called  uniform 
methods,  but  the  general  leaching  of  bark  and  the  use  of  the 
graded  decoction  on  the  packs,  in  the  order  of  their  coming 
in  and  going  out  of  the  yard,  must  be  conceded  to  be  our  com- 
mon practice,  and  to  this  extent  the  system  is  exclusively 
American  and  English. 

The  manner  of  running  liquors  from  the  leaches  to  the  yard 


THE  LEATHER  MANUFACTURE.  89 

is  by  covered,  inclosed  wooden  tubes  or  bored-out  logs,  either 
under  ground  or  under  covered  ways.  The  method  of  con- 
struction and  cost  of  these  will  be  stated  hereafter,  but  where 
heat  is  used  on  the  head  leach,  these  liquors  are  too  often 
sent  into  the  yard  warm,  or  even  hot,  and  when  thus  used, 
very  much  injury  to  both  color  and  buff  is  the  result.  Yet, 
as  ihese  head  or  strong  liquors  are,  or  should  be,  confined  to 
the  head  or  nearly  tanned  packs,  positive  damage  to  the  gel- 
atine of  the  hide  does  not  follow  to  the  extent  which  would 
bo  supposed ;  while  if  these  warm  liquors,  from  mistake  or 
ignorance,  go  to  the  half-tanned  or  green  packs,  " black  rot" 
is  almost  sure  to  result,  particularly  in  the  summer  season. 
The  damage  is  caused  by  the  decay  of  the  animal,  fiber — ac- 
tual decomposition  of  the  untanned  or  raw  hide.  The  ex- 
ternal appearance  of  this  damage  appears  as  a  sinking  in  of 
tlie  two  surfaces,  caused  by  a  general  disturbance  of  the  cen- 
tral tissues.  When  the  decomposition  proceeds  still  further,, 
and  the  surfaces  break,  partially  tanned  "puss"  exudes. 
This  disturbance  and  damage  has  been  popularly  denomina- 
ted the  "  black  rot,"  because,  upon  the  grain  side,  in  addition 
to  the  "  falling  away  "  appearance  spoken  of,  the  surface  turns 
black,  showing  dark  or  black  spots  wherever  this  damage  oc- 
curs, and  this  is  generally  in  the  thickest  and  best  portion  of 
the  hide. 

While  on  this  subject  of  latent  defects  and  damage,  perhaps 
it  is  as  well  to  state  the  experience  of  our  tanners  in  regard 
to  the  "white  spots,"  of  which  there  has  been  so  much  reason 
to  complain,  and  which,  even  w'th  our  conceded  ability  to 
remedy,  still  cause  great  depreciation  of  value  in  much  of 
our  sole  leather.  This  defect  occurs  from  imperfect  beam 
work.  In  the  sweating  process  the  hides  are  soaked,  milled 
and  sweated  within  a  week,  and  when  the  atmosphere  of  the 
sweats  and  the  nature  of  the  hides  favor,  the  hair  "  comes" 


90  THE  LEATHER  MANUFACTURE. 

quite  freely;  as  that  fact,  under  our  process,  indicates  tliat 
all  lias  been  done  that  is  necessary,  the  stock  is  turned  into 
the  liquor,  when,  in  fact,  the  workman  has  never  touched 
much  of-  the  grain  surface  of  the  hide,  thus  leaving  mucus 
and  grease.  Often  the  grain  has  been  saturated  with  the 
greasy  substances  of  the  animal,  which  are  not  overcome  or 
worked  off  by  the  beam  hand,  but  remain  to  resist  the  action 
of  the  liquor.  Some  tanners  call  this  "  mucus,"  but  the 
greasy  substance  which  causes  this  white  spot  is  different 
from  mucus,  as  will  be  demonstrated  by  a  little  examination. 

The  New  York  leather  trade,  several  years  ago,  offered  a 
reward  to  any  tanner  who  would  discover  a  remedy  for  this 
defect,  and  a  Mr.  Edson  came  forward  with  a  solution  .of  the 
difficulty.  He  discovered  that  potash,  soda  ash,  or  any 
strong  alkali,  applied  to  this  untanned  or  uncolored  white 
spot,  would  at  once  make  the  grain  take  the  coloring  matter, 
and  subsequently  receive  the  tannin.  This  was  a  perfect 
remedy,  and  led,  as  any  one  may  perceive,  to  the  cause  of 
the  trouble.  Whereas  other  tanners  ascertained  that  rubbing 
the  surface  with  pumice  stone  or  brick,  or  scraping  thoroughly 
with  a  knife,  would  measurably  relieve  the  damage,  the  real 
cause  of  the  difficulty  was  not  suggested  until  the  alkali  test 
was  applied,  and  then  we  all  comprehended  that  grease,  in 
some  form,  was  the  source  of  the  trouble,  and,  therefore,  to 
Mr.  Edson  was  awarded  the  valuable  consideration  offered  by 
the  trade.  If,  therefore,  hereafter,  any  tanner  suffers  from 
the  appearance  of  these  white  spots,  and  does  not  apply  the 
remedy,  he  has  only  himself  to  blame.  These  spots  may  be 
avoided  in  two  ways :  First,  by  thorough  working  on  the 
beam  ;  or,  second,  by  the  use  of  a  strong  alkali  on  the  spots 
affected,  after  the  sides  have  been  colored,  and  the  defect 
complained  of  discovered  in  the  handler. 

The  best  practical  method  to  overcome  these  spots  would, 


THE  LEATHER  MANUFACTURE.  91 

perhaps,  be  for  the  tanner  to  have  a  carboy  standing  in  his 
yard  with  either  a  strong  decoction  of  sal  soda  or  soda  ash, 
from  which  the  attendant  on  the  handlers  can  take  a  small 
portion,  and  by  the  use  of  a  rag  or  sponge  touch,  and  even 
slightly  rub,  the  affected  part.  It  will  cause  a  dark  or  even 
black  stain  at  first,  but  this  will  finally  disappear  in  the  after 
process.  Some  tanners  prefer  to  throw  the  sides  affected  on 
a  table  or  beam,  and  rub  or  scrape  the  spots  with  a  smooth 
steel  edge  ;  a  round  pointed  knife  is  serviceable  for  this  pur- 
purpos'-.  The  latter  course  can  only  be  pursued,  however, 
when  the  spots  are  small  and  infrequent.  My  judgment  is 
that  where  sufficient  care  is  taken  to  work  fully  over  the  grain 
in  the  beam  house  these  spots  will  not  be  encountered  in  the 
handlers. 

It  is  probable  that  if  hard  wood  ashes,  soda  ash,  or  sal 
soda,  were  freely  used  in  the  soaks  of  such  hides  as  usually 
give  this  trouble  (as,  for  instance,  dry  Western  and  Califor- 
nia), no  white  spots  would  ever  make  their  appearance  in  the 
handle  -s;  besides,  the  greasy  hides  would  soak  more  uni- 
formly. AYlien  a  pack  of  dry  hides  is  thrown  into  soak  in- 
discriminately great  injustice  is  done  the  "  sun  dried "  and 
greasy  portions,  from  their  more  persistent  resistance  of  the 
soak. 

The  question  has  often  been  raised  whether  the  sides 
should  be  laid  grain  or  flesh  up  in  the  layaways.  The  prac- 
tice is  to  lay  grain  up,  and  this  is  justified  on  the  ground 
that,  in  "hooking  up,"  the  grain  is  not  so  likely  to  be  scratched 
and  marked  as  it  would  be  if  the  sides  were  laid  flesh  up. 
If,  as  seems  quite  likely,  the  color  is  seriously  affected  (par- 
ticularly in  hemlock  tannages)  by  the  settling  of  the  coloring 
matter  on  the  grain,  and  a  deeper,  darker  red  is  the  result, 
then  tanners  may  well  inquire  whether,  in  their  attempt  to 
avoid  hook  marks,  they  do  not  entail  upon  their  stock  a  worse 


92  THE  LEATHER  MANUFACTURE. 

evil.     Besides,  it  may  be  asked  in  this  connection  whether  it 
is  not  probable  that  tannin  will  enter  the  fiber  of  the  hide 
more  naturally  from  the  flesh  than  from  the  grain  surface. 
The  pores  of  the  hide,  when  on  the  animal,  certainly  do  open 
their  valves  outward  from  the  flesh,  for  all  the  emanations  of 
the  animal  body  go  through  these  outward  opening  valves  or 
pores  of  the  skin,  which  never  receive  back  from  the  grain  to 
the  flesh.     "We  all  know  that  the  goat  and  shsep  skin  tanners, 
when  they  "sew  up"  their  skins,  keep  the  grain  outward, 
and  tan  altogether  by  pressure  from  within.     But  some  one 
may  ask,  Does  not  the  tan  liquor  surround  both  surfaces,  and 
seek   admittance   equally  from   each   side?      This   may  be 
answered  in  the  negative,  for  the  heavier  or  stronger  liquor 
settles,  and  when  the  sides  lie  upon  each  other  in  layers,  both 
the  strength  and  the  coloring  matter  tend  to  settle  downward. 
The  theory  is  that  when  the  tannin  comes  into  contact  with 
the  gelatine  of  the  hide  the  union  is  made  instantly,  and  then, 
if  both  the  hide  and  tannin  are  allowed  to  stand  in  perfect 
quiescence,  the  conclusion  is  drawn  that  not  only  does  the 
strong  liquor  settle,  but  it  does  its  work  instantaneously,  from 
underneath,  while  from  the  top  of  the   side  this  specific- 
gravity  principle  of  the  liquor  keeps  on  acting  for  a  consid- 
erable time,  forcing  downward  the  renewed  strong  liquor,  and 
bringing  itself  into  contact  with  the  untanned  fiber.      This 
may  be  refining  on  speculative  ideas,  but  such  a  theory  does 
prevail  among  some. 

One  of  these  theorizing  tanners,  within  the  knowledge  of 
the  writer,  always  acted  upon  this  idea,  and  made  it  his 
habit,  several  times  each  day,  to  walk  over  his  layaway  packs, 
stopping  to  press  his  weight  forcibly  on  each  as  he  passed. 
He  always  insisted  that  by  this  course  he  displaced  and  dis- 
turbed the  fixed  relation  of  the  liquor  to  the  gelatine  of  the 
hide,  and  brought  new  tannin  in  contact  with  the  hide.  This 


THE   LEATHER   MANUFACTURE.  93 

we  know,  that  agitation  of  the  fiber  and  frequent  replacement 
of  tannin  does  facilitate  the  process. 

The  last  or  fourth  layer  is  purposely  prolonged,  not  only 
to  fill  the  fiber  and  make  the  leather  firm,  but  also  to  bright- 
en the  color,  as  is  sure  to  result  from  the  acid  liquor,  which 
accumulates  with  age.  The  fiber  is  fairly  tanned  on  the 
third  layer,  but  the  filling  process — the  extra  weight,  indeed 
— is  made  on  this  layer,  and  the  tanner  who  fails  to  give 
ample  time  to  this  last  layer  must  be  content  with  inferior 
solidity  and  gains.  Can  leather  be  overtanned?  Yes.  It 
may  be  so  thoroughly  tanned  as  to  leave  no  grain  to  buff, 
and  really  no  life  or  elasticity  to  the  fiber. 


CHAPTEE    X. 
DKYING  AND  FINISHING. 

WASHING   AND   SCRUBBING    THE    LEATHER — THE     "  HOWARD     SCRUBBER  " — 

WHEEL    OR    DRUM    SCRUBBING DRAINING HOW    THE    ADMISSION    OF 

LIGHT    AND     AIR     SHOULD    BE    REGULATED     IN    DRYING DAMPENING 

BEFORE    ROLLING THE    FIRST    AND     SECOND     ROLLING EFFECT     OP 

THE  ROLLING   ON   THE  BUFFING    QUALITIES BLEACHING    WITH   SUGAR 

OF     LEAD   AND     SULPHURIC    ACID THE    WARM   SUMAC   BATH EFFECT 

OF   THE   LATTER   ON    CALFSKINS,    GRAIN   LEATHER,    ETC.      . 

From  the  last  layer  in  the  yard  the  finishing  process  begins. 
If  mistakes  have  been  made  and  defects  are  apparent  it  be- 
comes the  duty  of  the  finisher  to  consider  and  overcome  them. 
Where  a  uniform  system  prevails,  both  in  the  beam  house 
and  yard,  such  defects  should  not  be  of  frequent  occurrence ; 
but  whatever  they  are,  and  wherever  they  occur,  it  is  the 
duty  of  those  who  have  charge  of  the  drying  and  finishing 
loft  to  make  amends,  as  far  as  possible. 

The  first  duty  of  the  finisher  is  to  cleanse  the  leather  from 
all  sediment  and  extraneous  matter.  This  can  be  better 
begun  before  the  leather  has  been  exposed  to  the  air  than 
after  such  exposure.  For  this  reason  the  pack  should  te 
taken  in  hand  immediately  on  coming  from  the  layer,  when 
the  leather  should  be  thrown  into  clean  water,  or  may,  if  there 
are  stains  and  a  mottled  condition  of  the  grain,  be  thrown 
into  an  old  sour  liquor,  and  left  for  a  day  or  more.  "We  must 
bear  in  mind  the  object  to  be  attained,  namely,  to  cleanse  and 


* 

THE  LEATHER  MANUFACTURE.  95 

purify  the  grain  and  flesh.  This  can  be  done  in  various 
way s — first,  by  rinsing  and  hand  .  scrubbing  ;  second,  by  re- 
volving drum  wheels,  with  surfaces  covered  with  splint  brooms. 
This  method  is  covered  by  the  patent  of  Mr.  Howard,  and 
the  scrubbers  are  known  as  the  "Howard  scrubbers."  The 
third  plan  is  by  a  revolving  drum  wheel,  during  the  revo- 
lutions of  which  the  leather  is  washed  by  a  constant  tumb- 
ling and  turning  over  in  water,  which  is  freely  supplied. 
This  wheel,  in  its  application  to  such  service,  is  also  covered 
b}^  a  patent.  The  merits  of  each  of  these  processes  will  be 
considered  in  their  order,  but  before  presenting  the  remedy 
for  the  evils  which  necessitate  this  scouring  let  me  consider 
their  cause. 

If  the  liquors  are  obtained  from  the  press  leach  there  will 
be  no  sediment  or  discoloration  to  remove,  and  consequently 
nothing  more  will  be  required  than  rinsing  and  scrubbing 
with  a  hand  broom,  or  brush.  But  if  the  liquors  have  come 
from  the  "sprinkler  leach,"  or  from  the  ordinary  "flooding 
leach,"  then  there  will  have  accumulated  bark  dust  and  sed- 
iment, blended  with  resinous  matter,  which  will  attach  itself 
to  the  flesh  and  grain,  and  will  require  mechanical  power  for 
its  removal. 

The  "Howard  scrubber "  is  now  largely  relied  upon  to  re- 
move these  defects.  It  consists  of  two  revolving  rollers  or 
drums,  with  their  surfaces  coming  very  near  together,  to 
which  are  attached  brooms  or  brushes,  which  quite  meet. 
Through  these  scrubbing  surfaces  the  sides  are  made  to  pass 
— sometimes  once,  but  often  twice  and  three  times.  The 
friction  is  increased  by  holding  back  the  side  with  the  hand 
with  more  or  less  firmness.  Two  men  can,  with  this  machine, 
pass  thiough  about  500  sides  per  day,  and  do  the  work  well. 

More  recently  the  "wheel  "  or  "  drum  scrubber  "  has  come 
into  use.  This  consists  of  a  drum  wheel  about  six  to  eight 


96  THE   LEATHER  MANUFACTURE. 

feet  in  diameter,  four  or  five  feet  wide,  made  strong  enough 
to  resist  the  hammering  .process  of  the  revolving  sides  of 
tanned  leather,  which  are  made  to  "  thrash  "  around  in  tho 
inner  surface  of  the  wheel  as  it  revolves  slowly,  say  about 
twenty  revolutions  per  minute.  The  inner  surface  of  this 
wheel  is  furnished  with  pins  or  projections,  which  carry  the 
sides  around  with  the  motion  until  they  are  raised  sufficiently 
from  the  bottom  to  violently  agitate  the  fiber  by  their  drop- 
ping down,  and  by  the  friction  caused  by  the  sides  rubbing 
against  each  other  the  surfaces  are  cleansed,  very  much  on 
the  same  principle  as  iron  castings  are  now  made  smooth  by 
being  rubbed  against  each  other  in  a  revolving  wheel — or  as 
shoemakers'  pegs  are  polished  by  friction  and  contact — being 
revolved  in  bulk  inside  a  tank  or  hogshead.  It  is  claimed 
that  the  most  of  the  bark  sediment  or  accumulation  is  re- 
moved by  this  wheel  within  five  minutes,  and  as  about  ten  or 
fifteen  sides  can  be  thrown  in  at  a  time,  it  will  be  perceived 
that  the  cleansing  process  is  rapid  and  economical. 

Great  care,  it  appears  -to  me,  should  be  observed  lest  this 
wheeling  be  continued  too  long,  the  effect  of  which  would  be 
to  pound  out  the  weight  and  make  the  leather  soft.  The 
writer  is  assured  that  with  care  these  defects  can  be  avoided. 

"When  the  sides  have  been  thoroughly  cleansed,  by  means 
of  either  of  the  foregoing  processes,  they  are  usually  laid  in 
packs  to  drain,  but  in  doing  this  great  care  should  be  taken . 
to  place  flesh  to  flesh  and  grain  to  grain,  with  each  side  so 
exactly  covering  the  other  as  not  to  allow  the  flesh  of  one  to 
touch  the  grain  of  another.  Unless  this  precaution  is  taken 
the  strong  liquor,  which  is  absorbed  and  held  by  the  flesh  in 
undue  proportion,  in  spite  of  all  attempts  to  remove  it.  will 
impart  itself  to  the  grain  of  the  side  it  comes  in  contact  with, 
if  the  pack  is  unevenly  spread,  so  that  the  drainings  can  run 
down  and  stand  in  small  pools  on  the  grain  surface.  Such 


THE   LEATHER   MANUFACTURE.  97 

spots  will  be  marked  with  the  stain  of  the  bark  liquor  when 
the  leather  is  finished. 

The  most  ready  way  to  avoid  the  forming  of  these  "  cups  " 
is  to  throw  the  pack  over  a  "  half  log,"  cut  lengthwise,  whi  :h 
is  made  as  follows  :  Saw  a  hemlock  log,  two  feet  in  diameter, 
through  the  center ;  turn  the  concave  surface  up  and  the  flat 
surface  on  the  floor,  and  lay  the  pack  lengthwise  on  this  stick 
of  timber  ;  it  will  be  almost  impossible  in  this  way,  with  or- 
dinary care,  to  have  any  cavities  form  into  which  the  spent 
liquor  will  run  and  cause  these  stains. 

The  pack,  while  thus  exposed  to  the  air,  should  be  covered 
with  canvas,  to  prevent  the  edges  and  exposed  surfaces  from 
meeting  the  light  and  air ;  otherwise  such  portions  will  be- 
come darkened  to  such  an  extent  as  to  show  finally  great 
discoloration. 

After  the  pack  has  been  thoroughly  drained,  a  slight  coat 
of  fish  oil  should  be  put  on  the  grain  and  flesh  by  a  rag,  and 
the  leather  may  then  be  hung  up  to  dry.  If  the  Turret  dryer 
is  used,  or  the  principle  of  that  dryer  is  observed  in  the  con- 
struction of  the  building  in  which  the  leather  is  placed,  the 
perfect  control  of  the  light  and  air  thus  obtained  will  enable 
the  workman  to  keep  all  light  and  any  considerable  drafts  of 
air  from  the  leather  for  three  or  four  days,  or  until  the  sides 
are  fairly  stiff  and  dry  on  the  surfaces.  After  the  moisture 
has  been  evaporated  from  the  surfaces  air  may  be  admitted, 
but  not  a  strong  light,  for  the  free  admission  of  light  to  the 
leather  is  certain  to  darken  the  color.  Ten  days  will  dry  the 
heaviest  sole  leather  if  a  proper  drying  loft  is  employed,  but, 
whatever  time  is  requisite,  the  leather  in  all  its  parts  should 
be  thoroughly  dry  before  it  is  taken  down.  When  in  this 
condition  it  may  be  held  subject  to  the  call  of  the  roller. 

Two  days  at  least  before  the  leather  is  rolled,  the  "  damp- 
ening process "  should  begin.  The  sides  should  be  first 

7 


98  THE  LEATHER  MANUFACTURE. 

sprinkled  with  water  carefully,  both  on  grain  and  flesh,  and 
then  laid  down,  grain  to  grain,  and  flesh  to  flesh,  taking  care 
as  before  not  to  have  "  cups  "  form  where  liquor  stains  may 
occur.  After  a  period  of  a  few  hours  the  same  process  may 
be  repeated,  but  with  more  care,  making  certain  this  time 
that  ah1  parts  have  not  only  been  reached,  but  that  no  more 
water  has  been  applied  than  will  readily  absorb.  The  pack 
should  then  be  carefully  laid  in  a  large  wooden  box  or 
tight  room,  care  being  taken  to  pack  snugly,  so  as  to  get  in 
as  many  sides  as  possible,  and  at  the  same  time  to  prevent 
the  air  reaching  the  skirts  to  dry  and  discolor  them. 

If  the  dampening  process  has  been  attended  to  with  care, 
the  leather  will  be  in  condition  to  "  pack  "  under  the  roller 
without  "rebounding"  or  "  comingback ;"  but  to  make  sure  that 
all  the  parts  are  evenly  moistened,  great  care  should  be  taken 
by  the  attendant  to  re-sponge  both  grain  and  flesh  lightly 
before  the  sides  are  passed  to  the  roller,  taking  special  pains 
to  retouch  such  spots  as  have  lost  their  moisture,  and  become 
partially  dried.  It  will  also  serve  a  useful  purpose  to  pass 
an  oiled  rag  or  sponge  over  the  grain  surface,  to  prevent 
"  furring  up  "  under  the  roller  and  on  the  roller  bed.  The 
leather  should  be  so  prepared  that  the  whole  fiber  will  pack 
solid,  without  being  so  damp  as  to  induce  the  soluble  portion 
of  the  coloring  matter  to  press  through  the  grain,  as  will  be 
the  case  if  the  leather  is  roUed  when  too  damp.  "We  all 
know  that  snow  may  be  too  dry  as  well  as  too  damp  to  pack, 
and  the  same  is  true  of  leather.  The  happy  medium  should 
always  be  observed  to  secure  the  best  result. 

Since  our  tanners  have  been  trying  to  meet  the  tastes  and 
wants  of  the  German  market,  some  of  them  have  adopted  a 
somewhat  different  method  in  finishing  vitriol  raised  leather. 
Only  the  grain  is  dampened,  and  the  residue  of  the  fiber  io   ' 
rolled  dry,  or  nearly  so.     This  process  gives  a  fictitious  sub- 


THE  LEATHER  MANUFACTURE.  99 

stance,  and  a  harsh,  hard,  dry  fiber,  which  seems  to  corre- 
spond to  the  character  of  the  German  tannages,  but  cannot 
permanently  meet  the  wants  of  either  American  or  English 
manufacturers. 

All  sole  leather  should  have  the  stretch  taken  out  of  it  so 
completely  that  when  the  sole  is  cut  by  machinery  there  will 
be  no  waste,  as  it  goes  on  the  bottom.  It  should  exactly  fit, 
without  any  paring  or  loss. 

Leather  may  be  too  hard  as  well  as  too  soft,  but  it  cannot 
be  too  solid.  Keeping  in  view  the  distinction  between  "  hard" 
and  "  solid,"  the  reader  will  understand  that  solid  leather  is 
a  well-packed  fiber,  which  cuts  "  cheesy"  and  "  smooth,"  and 
not  dry  and  "  husky,"  as  much  of  the  vitriol  raised  leather 
cuts,  increasing  in  these  undesirable  qualities  with  age. 

The  leather  is  rolled  for  the  first  time  in  the  moist  ("  sam- 
mied ")  condition  previously  described.  The  grain  is  fairly 
flattened  and  made  smooth;  the  whole  fiber  is  firmly  packed; 
"but  there  remain  roller  marks  on  the  grain,  and  defects  which 
must  be  overcome.  How  shall  this  be  done  ?  Some  will  say 
— let  the  leather  be  fully  dried  and  then  brought  back  and 
rolled  on  the  flesh  side,  grain  side  to  the  roller  bed,  and  this 
will  remove  all  marks  on  the  grain  from  the  first  rolling,  and 
will,  besides,  leave  a  gloss  and  finish  on  the  grain  which  is 
most  desirable.  Much  can  be  said  in  favor  of  this  style  of 
finish,  and,  perhaps,  no  one  has  been  more  influential  in  in- 
troducing it  than  the  writer.  But  for  all  that,  it  is  not  the 
most  artistic  or  desirable.  It  will  do  on  hemlock  leather, 
where  mere  color  in  the  buff  is  sought,  but  where  both 
"color"  and  a  "  velvety "  buff  is  desirable,  i.e.,  where  the 
bottom,  after  being  buffed,  is  to  present  a  "  soft  nap,"  and  at 
the  same  time  a  lively  and  beautiful  flesh  color,  then  some 
other  process  must  be  adopted.  This  other  and  better  pro- 
cess is  a  second  rolling,  immediately  or  very  soon  after  tho 


100  THE   LEATHER   MANUFACTURE. 

first.  The  sides,  after  the  first  rolling,  may  be  spread  about 
the  loft,  and  within  an  hour  after  the  first  rolling  the  second 
rolling  should  take  place  from  the  flesh  side,  as  the  first  was 
from  the  grain.  It  may  even  be  of  service  to  slightly  re- 
dampen  the  grain  in  spots,  if  the  leather  is  allowed  to  re- 
main as  much  as  an  hour  in  a  dry  atmosphere  between  the 
first  and  second  rolling. 

The  care  required  to  finish  "  union  crop  "  leather,  as  well 
as  pure  oak,  is  incomparably  greater  than  is  usually  be- 
stowed on  the  ordinary  hemlock,  and  yet  the  time  is  prob- 
ably not  far  distant  when  the  same  care  will  fully  compen- 
sate the  tanner  in  the  latter  as  in  the  former  tannage,  par- 
ticularly where  slaughter  hides  are  used.  Some  of  our  union 
leather  tanners  are  now  turning  their  attention  to  pure  hem- 
lock tannage,  and  their  greater  success  in  producing  hemlock 
leather  justifies  the  impression  that  more  care  in  the  finish 
of  slaughter  hemlock  will  well  repay  the  tannner.  One  con- 
tinent has  come  to  be  well  nigh  convinced  that  hemlock  bark 
is  as  serviceable  in  tanning  as  oak,  and  it  is  quite  within  the 
range  of  possibilities  that  another  decade  of  years  will  bring 
the  whole  Eastern  World  to  this  conviction. 

The  branch  of  the  finishing  business  which  may  be  called 
the  bleaching  process  might  profitably  occupy  a  chapter  by 
itself,  but  as  the  writer  does  not  pretend  to  fully  understand 
— and,  if  he  did,  would  not  commend  the  various  devices  of 
bleaching  leather  by  sugar  of  lead  and  sulphuric  acid,  which 
is  the  most  common  practice  in  general  use  among  fair  lea- 
ther manufacturers — the  suggestions  on  this  subject  will  be 
compressed  in  this  chapter.  The  practice  now  is  to  dip  the 
sides  alternately,  first  into  a  bath  of  sugar  of  lead,  and  then 
into  one  of  sulphuric  acid,  until  the  coloring  matter  of  the 
hemlock  is  fully  removed.  This  bleaching  process  produces 
an  immediate  effect  that  is  almost  magical,  but  when  the 


THE   LEATHER   MANUFACTURE.  101 

finished  leather  is  exposed  to  the  air  and  light  for  any  con- 
siderable time  the  delicate  pink  and  cream  color  turns  to  a 
"  murky  brown,"  and  the  finish  is  in  all  respects  most  objec- 
tionable. The  only  natural  and  honest  bleaching  process 
known  to  the  writer  is  that  of  "  sumac  baths."  After  the 
hemlock  sides  have  been  cleansed  of  all  extraneous  matter, 
as  before  described,  by  the  most  effective  mechanical  device 
known,  it  must  then  be  hung  in  a  vat  of  warm  sumac  liquor, 
and  plunged  frequently  for  one  day  (and  even  a  few  hours 
will  sensibly  affect  the  color).  Usually  one  bag  of  Virginia 
sumac  will  suffice  for  a  pack  of  one  hundred  sides.  This  pro- 
cess will  cost  about  five  dollars  for  a  pack,  or  five  cents  per 
side,  weighing  fifteeen  to  twenty  pounds.  The  sumac  liquor 
forms  a  vegetable  acid,  which  acts  most  kindly  on  the  grain 
of  hemlock  slaughter  leather,  not  only  removing  (neutraliz- 
ing) the  color,  but  softening  the  grain,  and  contributes  very 
much  to  the  whiteness  and  clearness  of  the  buff.  Hemlock 
leather  thus  bleached  will  retain  its  improved  color  for  a  long 
time,  and  never  go  back  to  that  muddy  and  objectionable 
color  so  common  where  other  bleaching  processes  are  em- 
ployed. As  it  is  the  acid  that  effects  the  object,  sought,  the 
sumac  liquor  should  be  retained  long  after  its  tannin  has  de- 
parted. As  a  mere  tannin  agent  it  is  only  valuable,  as  all- 
goat  and  sheep  skin  tanners  comprehend,  while  it  is  fresh, 
before  the  acid  forms  ;  but  for  the  purpose  of  bleaching  hem- 
lock leather,  it  is  questionable  whether  the  old  cast  off  sumac 
of  the  morocco  dresser  is  not  quite  as  valuable  as  new  sumac. 
At  all  events,  some  experiments  that  have  been  tried  go  to 
this  extent  in  their  conclusions. 

Slaughter  hemlock  leather,  tanned  with  liquors  of  moder- 
ate strength,  say  16  to  20  degrees,  from  the  press  leach,  will 
come  out  with  a  color  that  is  between  the  lemon  and  the 
orange  ;  if  to  this  we  add  the  warm  sumac  process,  we  get 


102  .     THE   LEATHER   MANUFACTURE. 

a  color  so  nearly  a  light  lemon  or  a  flesh  color  as  to  meet  the 
requirements  sought  in  the  best  oak  leather.  Indeed,  for  all 
fine  work,  whether  men's  or  women's,  the  buff  is  superior  to 
that  of  most  pure  oak  tannages,  for  these  have  a  "sickly 
white"  which  soils  much  more  readily  on  the  bottom  than 
the  flesh  color  of  the  hemlock  or  union  tannages  bleached  as 
here  indicated. 

This  bleaching  process  is  particularly  serviceable  on  calf, 
a:id  all  grain  finished  leathers,  including  harness  and  bridle. 
No  purely  hemlock  tannage  will  "  take  the  blacking  "  so  well 
as  leather  which  has  undergone  this  treatment.  With  it,  hem- 
lock grain  leather  can  be  made  to  hold  its  color  almost  equal 
to  that  of  pure  oak  tannage.  Calfskins  properly  tanned  in 
hemlock  can,  by  this  bath  of  warm  sumac  liquor,  be  made 
equal  in  color  to  the  best  French,  German  or  Swiss  ;  indeed, 
the  resemblance  is  much  greater  than  that  of  skins  tanned  by 
pure  oak  tannage,  for  the  French  color  is  controlled  by  the 
"  larch  "  bark,  the  equivalent  of  our  "  spruce,"  which,  as  all 
know,  is  a  modified  hemlock  in  color.  Above  all  these  con- 
siderations actual  experiments  seem  to  indicate  that  this  su- 
mac process  will  add  enough  to  the  weight  to  pay  for  its  cost. 
However  this  may  be,  it  will  add  greatly  to  the  intrinsic  qual- 
ities of  all  upper  stock  and  much  to  the  beauty  of  the  buff  in 
sole  leather. 

As  directly  connected  with  this  subject,  it  may  be  men- 
tioned that  for  many  years  the  union  crop  leather  tanners 
used  "  sour  milk "  to  wash  the  grain  between  the  first  and 
second  rolling.  This  treatment  not  only  "  lightened  up  "  the 
whole  complexion,  but  removed  clouded  spots  and  even 
stains,  and  was  withal  a  most  harmless  bleaching  process,  as 
the  light  and  air  did  not  affect  unfavorably  the  buff  any 
more  than  in  any  of  the  vegetable  processes.  But  mineral 
acids  are  objectionable  and  should  be  avoided. 


CHAPTEE    XI. 

THE  CAUSES  WHICH  AFFECT   COLOE  AND  ASSIST  IN 
THE  MAKING  OF  A  VALUABLE  EMBOSSING  GEAIN. 

WHY  LEATHER  SHOULD    BE  THOROUGHLY  DRIED STRUCTURE   OF  THE  GRAIN 

IMPORTANCE    OF   A   PERFECT   FINISH CARE   TO  BE  TAKEN  TO  AVOID 

STAINS  AND  DISCOLORATION "  CUIR  "  COLOR THE  NATURAL  HEMLOCK 

COLOR "  RUSSIA    LEATHER  "  COLOR FRAUDS    IN    SELLING   HEMLOCK 

FOR  OAK  LEATHER  DURING  THE  WAR COLORING   TO    BE   DONE   IN  THE 

HANDLERS EFFECT  OF  "  STRIKING  "  THE  GRAIN. 

In  the  preceding  chapter  it  has  been  insisted  upon  that 
leather  should  be  thoroughly  dried  before  being  taken  down 
to  roll.  The  importance  of  great  care  in  this  matter  may 
not  be  appreciated  without  some  further  attention  to  the  pe- 
culiar nature  of  the  "  grain J>  and  an  examination  of  the 
•causes  which  affect  its  structure,  including  its  color  and  its 
embossing  qualities.  Some  tanners,  defending  their  practice, 
say,  "  Why  occupy  so  much  time  in  thoroughly  drying  the 
fiber  of  the  leather,  and  then  immediately  thereafter  dampen- 
ing down  again  ?-"  At  the  expense  of  seeming  over  nice,  the 
writer  will  explain  the  reasons  for  taking  this  course. 

The  immediate  outside  grain  of  leather  is  a  thin  tissue, 
hardly  thicker  than  thin  paper.  Next  to  this  is  an  inner 
grain,  several  times  thicker  than  the  first,  and  very  much 
more  spongy  in  its  nature.  Together  these  two  structures 
are  usually  called  "  the  grain,"  and  for  the  purposes  of  this, 
discussion  may  be  treated  as  one. 


104  THE  LEATHER  MANUFACTURE. 

Much  of  the  value  of  sole,  harness,  trunk  and  other  leathers 
depends  upon  the  appearance  and  condition  of  this  grain. 
Upon  this  outer  surface  the  harness  maker  and  saddler  stamp 
their  forms  and  make  their  ornaments ;  the  currier  and  fin- 
isher stamps  or  presses  the  grain  with  dies,  making  imitation 
hog,  goat  or  seal  skins  out  of  ordinary  neats  leather.  The 
boot  and  shoe  manufacturer  first  buffs,  then  stamps  and 
otherwise  embellishes  the  bottom  of  his  ladies'  and  gentle- 
men's fine  work,  on  this  grain,  and  the  manufacturers  of  the 
finsr  leather  fabrics  emboss  this  surface  with  the  most  artis- 
tic forms.  To  enable  these  impressions  to  be  made  with 
proper  effect  and  remain  lasting — retaining  permanently  both 
form  and  color — the  grain  must  be  "clear,"  "bright"  and 
"perfect"  as  to  color,  and  "mellow,"  "elastic"  and  yet 
"  firm  "  in  structure. 

This,  then,  is  the  nature  of  the  surface  or  grain  which  is 
to  bs  kept  bright,  and  from  which  all  coloring  matter  must 
have  been  wa  heel  and  cleansed  as  far  as  possible  by  previous 
manipulation.  If  any  device  could  be  employed  to  pack  the 
main  fiber  of  the  sole  leather,  and  at  the  same  time  leave  the 
grain  perfectly  smooth,  it  would  be  most  desirable  not  to 
pack  or  compress  this  grain  at  all,  but  leave  it  soft  and  im- 
pressible for  the  artisan  who  comes  after  the  tanner ;  but  in- 
asmuch as  the  inner  fiber  cannot  be  compressed  by  any 
known  means  without  also  compressing  the  grain,  the  next 
best  thing  to  do  is  to  so  manage  as  to  leave  this  grain  as  soft, 
elastic  and  compressible,  and  also  as  free  from  coloring  mat- 
ter as  possible. 

It  is  found  by  experience  that  the  coloring  matter  of  the 
bark,  when  in  a  soluble  condition  in  the  fiber,  will  spread, 
when  compressed,  almost  as  readily  as  ink  on  paper,  and  for 
this  reason,  after  washing  and  cleansing  the  grain,  it  is  found 
desirable  to  fasten  the  coloring  matter  in  the  fiber  by  evap- 


THE  LEATHER  MANUFACTURE.  105 

orating  all  the  water,  which  will  leave  the  coloring  matter  in 
a  dry,  insoluble  and  fixed  condition.  This  condition  must 
not  be  disturbed — certainly  not  to  the  extent  of  making  it 
soluble,  by  any  after  process  of  wetting;  'if  that  is  done,  the 
pressure  of  the  roller  will  bring  the  coloring  matter  to  the 
surface,  and  nullify  all  the  advantages  gained  by  the  original 
washing  and  scrubbing,  for  the  grain  is  almost  as  porous  and 
as  susceptible  of  receiving  stain  as  blotting  paper,  and,  when 
in  a  natural  and  proper  condition,  as  impressible  under 
heavy,  as  wax  is  under  light  pressure. 

All  that  has  or  can  be  said  of  the  proper  treatment  of 
leather  to  get  rid  of  coloring  matter,  after  it  has  been  im- 
properly placed  in  the  fiber,  should  be  subordinated  to  the 
better  method  of  not  allowing  the  coloring  matter  ever  to  go 
in  the  leather  at  all,  or  certainly  not  to  the  damaging  extent 
which  would  render  the  extreme  methods  of  mineral  bleach- 
ing necessary.  It  is  possible  to  extract  the  tannin  from  even 
our  hemlock  bark  without  so  overcharging  it  with  coloring 
matter  as  to  damage  the  buffing  qualities  of  the  leather.  It 
is  not  necessary  that  all  our  leather  should  be  white,  or  cream 
color;  any  other  color,  if  only  natural  and  bright,  is  intrinsi- 
cally as  handsome  and  appreciable.  It  is  only  because  the 
red  color  of  the  hemlock  is  thought  to  be  extraneous  that  it 
is  regarded  as  objectionable.  It  is  because  this  color  is 
thought  to  indicate  our  inferior  quality  or  workmanship  that 
causes  leather  having  it  to  be  condemned. 

The  writer  saw,  in  one  of  the  first  boot  and  shoe  manu- 
facturers' show  windows  in  London,  the  best  English  bend 
bottoms  stained  red,  or  in  very  close  imitation  of  our  hem- 
lock. This  was  his  trade  mark,  and  had  been  for  many 
years.  There  was  no  attempt  at  buffing,  such  as  we  ap- 
preciate in  this  country,  but  the  bottoms  were  made  per- 
fectly smooth  with  the  the  "  long  stick."  Now,  this  only  proves 


106  THE   LEATHER   MANUFACTURE. 

that  there  is  no  standard  color  which,  of  itself,  gives  value. 
The  bright  hemlock  color  is  now  sought  in  pocket-books, 
satchels,  ladies'  belts,  bookbinders'  leather — and,  indeed, 
in  all  those  leathers  which  go  to  make  up  the  "art  work," 
of  which  leather  is  the  foundation.  The  French  word 
"cuir,"  for  leather,  is  to-day  the  name  of  the  prevailing 
fashionable  color — and  this  color  is  absolutely  fabricated 
from  hemlock  bark ;  yet  when  it  is  found  in  sole  leather  it 
seems  a  badge  of  disfavor,  to  be  got  rid  of  by  any  means, 
however  artificial  and  even  damaging  to  the  intrinsic  qual- 
ity of  the  structure  of  the  fiber. 

The  fashionable  "cuir"  color  can  be  most  artistically 
made  and  preserved  with  pure  hemlock  tanning,  if  only  too 
much  heat  is  not  used  in  extracting  the  strength  of  the  bark. 
For  fear  that  all  may  not  understand  what  is  the  limit  of 
heat  permissible,  it  may  be  said  that  no  tanner  who  desires 
to  make  the  best  color  possible  should  use  over  80  degrees  of 
heat  on  his  bark.  Hemlock  bark  liquors,  obtained  with  this 
limited  heat,  applied  to  pelts  or  hides  properly  prepared,  en- 
tirely freed  from  all  lime,  will  produce  a  color  in  almost  exact 
imitation  of  the  French  "  cuir  "  color,  or,  to  put  the  expres- 
sion into  English,  the  "  hemlock  tan  color." 

The  celebrated  Eussia  leathers  that  enter  so  largely  into 
the  fine  "  Yienna  leather  goods  "  are  originally  of  a  light 
lemon  color,  produced  by  the  willow  bark  with  which  they 
are  tanned,  and  they  are  afterward  changed  by  dyewoods  and 
mordants  into  various  colors;  the  most  p  pular  is  that  al- 
ready indicated — indeed,  it  is  sometimes  called  a  "  Eussia 
leather  color  "  by  way  of  designation,  and  yet  all  Eussia  lea- 
ther as  seen  in  the  arts  is  colored  artificially. 

A  curious  train  of  circumstances  developed  the  impolicy  of 
"  hiding  our  true  colors  "  during  the  recent  rebellion.  The 
army  oificers  imbibed  the  prejudice  which  generally  prevails 


THE  LEATHER  MANUFACTURE.  107 

that  oak  tanned  leather  was  far  superior  to  hemlock,  and 
were  influential  in  demanding  this  kind  of  tannage  in  all  their 
army  equipment  work,  such  as  shoes,  belts,  harness,  etc.  All 
of  the  earlier  contracts  specified  that  the  'leather  should  be 
made  from  "  oak,"  and  in  some  of  the  departments  "white 
oak  "  tannage  was  called  for.  Soon  the  disparity  between 
the  price  of  hemlock  and  oak  rough  leather  became  so 
marked  that  the  temptation  to  obtain  in  some  way  for  hem- 
lock leather  the  higher  prices  paid  for  oak  became  too  great 
to  resist,  and  curriers  found  a  way  to  bleach  the  hemlock 
even  to  a  lighter  color  than  the  natural  oak,  but  by  a  process 
which  greatly  damaged  the  intrinsic  quality  of  the  leather. 
One  of  the  first  discoveries  made  of  this  fraud  was  the  find- 
ing of  a  large  lot  of  bayonet  scabbard  sheaths  that  had  so 
rusted  the  steel  which  they  were  made  to  cover  and  hold  as 
to  make  both  leather  and  contents  perfectly  worthless.  The 
writer  was  c  died  on  by  the  Government  to  determine  the 
cause  of  this  damage.  The  decision  was  that,  by  reason  of 
the  mineral  salts  used  in  bleaching,  the  dampness  in  the  at- 
mosphere collected  an  amount  of  moisture  in  the  leather 
which  caused  the  rust  on  the  steel.  Then  how  could  this 
damage  be  prevented  in  the  future  ?  was  the  practical  ques- 
tion to  be  determined.  My  suggestion  was,  to  strike  from 
the  requisitions  the  demand  for  "  oak  tanned  leather,"  and 
thus  remove  all  temptation  to  make  artificial  oak ;  but  this 
practical  advice  was  not  heeded,  and,  more  or  less,  during  the 
whole  four  years  of  our  war,  the  Government  paid  for  oak 
leather  and  got  greatly  damaged  hemlock.  This  policy  on 
the  part  of  army  officers  cost  the  Government  millions  of  dol- 
lars, and  the  regulations  under  which  this  mistake  was  com- 
mitted are  still,  to  a  considerable  extent,  in  force. 

The  first  and  best  thing  to  do  then  is  not  to  overcharge  the 
tannin  with  the  coloring  matter  by  the  use  of  heat,  and 


108  THE  LEATHER  MANUFACTURE. 

second,  if  it  is  so  overcharged,  to  get  rid  of  it  by  washing  and 
scrubbing  and  the  use  of  vegetable  acid,  such  as  a  warm 
sumac  bath,  for  instance.  A  single  liquor  overcharged  with 
coloring  matter  in  the  earlier  stages  of  tanning  will  often 
leave  its  effect  so  permanently  on  the  pack  as  to  defy  all 
after  correction. 

It  is  a  mistake  too  often  made  by  tanners  to  suppose  that 
the  coloring  of  the  pack  is  effected  by  the  last  layers.  Ordi- 
narily the  color  given  in  the  handlers  is  carried  through  to 
the  end.  Start  the  color  right,  create  the  proper  mordant  in 
the  handlers,  and  then  strong  and  even  highly  colored  liquors 
may  be  used  without  causing  serious  damage.  The  writer 
once  saw  a  tanner  attempt  to  make  union  crop  leather  with 
the  usual  quantity  of  oak  bark,  by  putting  his  oak  in  at  the 
wrong  time;  he  thought  he  should  "finish  off"  with  oak, 
whereas  he  should  have  used  his  oak  as  a  mordant  in  his 
handlers  and  early  layaways;  the  result  was,  as  might  have 
been  expected — failure.  There  is  good  reason  to  think  our 
English  friends  have  made  this  mistake  in  using  our  hemlock 
extract.  They  have  used  the  extract  at  too  early  a  period, 
hoping  to  cover  it  up  by  their  light  coloring  materials  at  the 
end — whereas,  if  they  had  colored  their  packs  with  terra  and 
valonia,  and  put  the  hemlock  extract  in  their  last  layers,  they 
would  have  produced  a  different  result. 

The  English  custom  of  allowing  their  packs  to  "  sweat  "  in 
piles  before  "  striking  out  the  grain  "  is  founded  on  a  sensible 
idea,  and  the  practice  even  now  of  "  striking  "  the  grain  rath- 
er than  rolling  the  whole  substance,  is  based  on  the  practical 
wants  of  the  trade.  By  this  process  the  pelt  is  held  in  its 
natural  state.  The  thickness  is  maintained,  the  edges  (backs) 
are  rubbed  up  and  made  to  appear  full,  and  thus  a  market 
value  secured  which  would  be  sacrificed  if  the  leather  were 
dampened  and  rolled  as  is  our  custom. 


THE  LEATHER  MANUFACTURE.  109 

Whether  the  manufacturers  of  Great  Britain  and  Germany 
will  ever  become  accustomed  to  our  compressing  process,  and 
give  us  credit  for  plumpness  which  we  seem  not  to  have,  is  a 
question  to  be  determined  by  future  experience.  If  we 
change  our  rolling  for  a  stamping  process,  and  make  our  fiber 
hard,  while  at  the  same  time  we  compress  it,  we  certainly 
shall  suit  our  German,  Swiss  and  French  customers,  for  this 
is  the  method  followed  by  them  in  finishing  sole  leather. 


CHAPTER    XII. 
CONSTRUCTION  OF  TANNERIES— THE  TURRET  DRYER. 

HOW    THE    ADMISSION    OF    LIGHT    AND    AIR  IS  CONTROLLED   IN  THE   TURRET 

DRYER ITS    CAPABILITIES   FOR   DRYING   LEATHER    IN    QUICKER    TIME, 

WITHOUT   REGARD    TO    THE   WEATHER ITS    CONSTRUCTION,    AND    HOW 

ITS  CAPACITY  SHOULD  BE  PROPORTIONED  TO  THAT  OF  THE  YARD HOW 

AND  WHEN  HEAT  SHOULD  BE  USED HOW  TO  PREVENT   DISCOLORATION 

OF  THE  LEATHER SAVING  OF  LABOR  IN  THE  TURRET  DRYER. 

About  the  year  1864,  at  Sparrowbush,  N".  Y.,  the  first  turret 
dryer  was  erected.  It  was  a  six-story  structure,  with  most 
of  the  improvements  found  in  the  present  dryer.  There  is 
nothing  new  in  drying  leather  in  a  tall  building.  Many  of  the 
old  tanneries,  built  as  long  ago  as  1830,  had  three  lofts  over 
the  whole  size  of  the  tannery ;  the  floors  in  the  two  upper 
lofts  were  latticed,  and  were  therefore  in  this  respect  like  the 
present  turret  form  of  dryer.  But  the  principle  claimed  for 
this  improved  turret  dryer  is  that,  both  as  to  air  and  heat, 
there  is  perfect  control,  whereas,  with  any  drying  loft  hereto- 
fore in  use,  the  damp  air  of  the  yard  found  its  way  up  through 
the  lofts,  and  in  all  cases  there  were  opening  windows  from 
each  loft,  which  were  depended  upon  to  admit  the  external 
air,  so  that  substantially  all  the  air  obtained  came  in  through 
these  upper  openings.  The  effect  was  that  the  leather  hang- 


THE  LEATHER  MANUFACTURE.  Ill 

ing  near  the  openings  dried  rapidly,  while  those  sides  hanging 
in  the  center  of  the  loft  remained  unaffected,  so  that,  before 
they  could  be  dried,  they  were  required  to  be  transferred ; 
often  they  were  many  times  "  shifted."  This  shifting  process 
was  particularly  necessary  in  the  winter  time,  when  the  large 
box  stoves,  burning  wood,  placed  in  different  portions  of  the 
lower  loft,  or  in  the  yard  and  beam  house,  caused  the  sides 
hanging  near  to  dry  rapidly  and  greatly  to  discolor,  while  at 
twenty  feet  distant  the  leather  would  be  frozen  solid. 

The  difficulties  and  great  delays  in  drying  sole  leather  by 
any  of  the  old  methods  were  among  the  most  annoying  inci- 
dents of  the  tanners'  life.  All  these  are  entirely  removed  by 
the  turret  dryer.  There  is  now  an  absolute  certainty  as  to 
the  time  when  the  leather  will  be  dry,  and  this  does  not  in 
any  necessary  degree  depend  on  the  state  of  the  weather. 

Among  the  advantages  of  this  new  form  of  dryer  are  the 
following : 

1.  Drying  in  one-third  the  time — thus  saving  insurance 
and  interest. 

2.  Drying  without  regard  to  the  state  of  the  weather — thus 
at  all  times  keeping  the  rollers  supplied. 

3.  Drying  much  more  uniform  in  color. 

4.  Drying  without  shifting,  or  labor  of  any  kind  except  to 
"hang  up"  and  "take  down." 

These  are  some  of  the  economies  of  the  turret  system  of 
drying,  but  they  might  be  enlarged  upon.  The  principle 
claimed,  as  already  stated,  is  the  absolute  control  of  heat, 
light  and  air ;  with  these  three  elements  under  control,  it 
will  be  admitted  that  all  the  advantages  claimed  must 
follow. 

The  building  may  be  any  number  of  stories  high  ;  some 
are  but  three  or  four,  and  others  are  seven  and  eight.  Of 
co-irse,  to  erect  a  building  high  enough  to  contain  eight 


112  THE   LEATHEK    MANUFACTURE. 

stories  would  require  very  heavy  timbers,  and  from  botli  ob- 
servation and  experience  the  writer  would  recommend  but 
five  stories,  each  about  seven  feet  in  the  clear  between  beams 
—just  high  enough  for  a  man  to  pass  with  his  hat  on.  This 
structure  need  not  be  made  of  very  heavy  timber,  and  conse- 
quently would  be  inexpensive  as  compared  with  those  build- 
ings that  run  up  so  high.  The  question  of  convenience  of 
elevating  the  leather,  whether  in  the  higher  or  lower  turret, 
need  not  be  taken  into  the  account,  as  this  is  done  by  ma- 
chinery. The  building  should  be  about  two  spans  of  timber 
wide — say  forty  feet — with  two  rows  of  posts,  equidistant 
from  the  sides.  Longitudinally  with  the  two  rows  of  posts 
should  run  a  tight  board  partition,  with  intersections  at  every 
ten  feet  extending  to  the  sides.  This  would  cut  the  space  up 
into  two  rows  of  rooms  of  about  10  by  12  feet  each,  with  a  cen- 
ter passage  of  about  13  feet.  The  roof  is  made  in  the  usual 
latticed  lantern  form. 

All  the  floors  above  the  first  or  ground  floor  should  be  lat- 
ticed, and  the  rooms  would,  of  course,  be  immediately  above 
each  other,  so  that,  if  the  building  were  five  stories  high, 
there  would  be  five  rooms  10  by  12  feet  each,  standing  one 
above  the  other,  and  there  should,  of  course,  be  just  as  many 
of  these  rooms,  or  series  of  rooms,  as  would  be  required  to 
dry  the  stock  of  the  yard,  whatever  its  capacity  might  be. 

Each  one  of  these  rooms  will  contain  one  pack  of  a  hundred 
or  one  hundred  and  twenty  sidos,  depending  upon  the  weight 
of  leather,  and  will  dry  the  same  in  ten  days.  This  would 
give  the  series  of  five  rooms  the  capacity  of  drying  fifty  packs 
in  ten  days,  or  about  fifty  sides  of  heavy  sole  leather  each 
day.  Just  so  many  times  as  fifty  will  go  into  the  entire  daily 
production  of  the  yard  will  the  tanner  require  duplicates  of 
this  series  of  rooms. 

The  rooms  on  the  first  floor  should  be  supplied  with  steam 


THE  LEATHER   MANUFACTURE.  113 

pipe,  laid  on  the  floor,  or  raised  a  few  indies  only  by  strips 
of  hard  wood,  covered  with  hoop  iron.  The  piping  furnishing 
heat  for  each  of  these  rooms  should  be  under  separate  con- 
trol, so  that  not  only  could  the  steam  be  turned  on  or  off  from 
each,  but  any  degree  of  heat  might  be  admitted. 

All  the  packs  taken  out  in  one  day,  or  in  two  or  more  days 
in  succession,  should  go  in  one  of  these  sections,  so  that  the 
condition  of  the  leather  may  be  as  nearly  uniform  as  possible 
in  each  set  of  rooms.  The  leather  is  hung  up  on  sticks  in 
double  rows,  leaving  a  passage  of  nearly  two  feet  between. 
For  the  first  three  or  four  days  no  steam  should  be  allowed 
in  the  pipes  or  the  section,  nor  should  the  trap  doors  which 
lead  outwardly  be  opened  but  slightly  if  the  weather  is  warm 
or  the  winds  blow  high,  but  in  the  fall,  or  when  the  weather 
is  overcast,  the  lower  trap  doors  may  be  safely  left  open. 
About  the  third  or  fourth  day  a  very  low  degree  of  steam 
heat  may  be  allowed  in  the  pipes,  and  this  may  be  gradually 
increased  until  the  seventh  to  the  tenth  day,  when  it  may 
certainly  be  premised  that  the  leather  will  be  fully  dried ; 
then  all  the  sides  in  both  tiers,  and  in  all  of  the  five  rooms, 
will  be  dried  about  the  same  time,  and  may  all  be  taken  out 
and  replaced  by  other  sides.  The  writer  has  known  turrets 
to  be  so  actively  worked  as  to  turn  out  stock  in  seven  days, 
but  ten  days'  time  is  not  too  much,  since  it  is  very  important 
not  to  hurry  the  drying  the  first  few  days. 

It  has  not  been  stated  that  the  center  passageways  should 
be  lighted  by  ero^ss  sections  leading  to  the  windows,  nor  that 
each  room  should  contain  one  small  window  close  to  the  top, 
(but  to  admit  light  only),  nor  that  there  should  be  no  open- 
ings except  at  the  base  of  the  lower  room,  with  the  air  lead- 
ing directly  on  the  piping — all  these  are  questions  of  detail 
that  will  be  studied  by  any  tanner  who  attempts  to  replace 
his  old  method  by  this  new  and  better  one — f  jr  often  the  gen- 


114  THE   LEATHER   MANUFACTURE. 

eral  plan  here  outlined  must  be  modified  to  meet  the  new 
conditions. 

The  "  turret  dryer "  is  beyond  all  question  the  most 
thorough  and  efficient  method  yet  devised  for  drying  lea- 
ther, and  in  some  of  its  modified  forms  should  be  adopted 
by  all  tanners.  The  difference  in  the  temperature  of  the 
atmosphere  at  the  ground  and  at  an  altitude  of  40  or  50  feet 
would,  of  itself,  create  a  draft,  as  is  well  illustrated  by  the 
erection  of  "stacks"  or  "chimneys"  for  the  passing  off  of 
smoke  or  gas.  But  if  to  the  natural  action  caused  by  the 
difference  in  the  temperature  we  add  a  little  steam  heat,  a 
steady,  yet  moderate  circulation  will  be  maintained  from  the 
bottom  toward  the  top  or  openings  of  this  structure,  carrying 
upward  and  off  the  dampness  of  the  leather,  without  creat- 
ing such  violent  currents  of  air  as  to  injure  the  color. 

It  is  believed  that  the  principle  which  underlies  this  meth- 
od of  drying  sole  leather  could  be  applied  with  equal  advant- 
f\ge  to  all  other  kinds  of  leather — calf,  upper,  harness,  sheep, 
goat,  and  particularly  such  of  these  as  are  to  be  finished 
"  fair,"  without  injury  to  the  color  of  the  grain. 

Returning  to  the  construction  of  these  turrets,  it  may  be 
remarked  that  the  center  passageways  will  be  found  useful  in 
affording  room  to  run  the  trucks  with  green  leather,  or  to 
store  the  dry  leather  awaiting  the  roller.  Some  tanners  pre- 
fer to  have  shutes  running  through  each  loft,  down  which 
they  slide  the  leather  as  soon  as  dry,  to  be  piled  on  the  low- 
er floor.  Others  make  their  lattice  floors  of  a  temporary  or 
movable  structure,  so  that  the  whole  contents  of  each  room 
is  dropped  down  into  the  lower  room,  including  all  the  sticks 
on  which  the  leather  has  been  hanging.  The  writer  does  not 
thiiik  this  a  good  plan,  on  the  whole,  since  the  extra  labor  of 
separating  the  leather  from  the  mass  of  sticks,  and  carrying 
them  back  to  their  proper  place,  is  about  as  much  trouble  as  it 


THE  LEATHER  MANUFACTURE.  115 

would  be  to  take  the  sides  down  in  the  rooms,  and,  with  the 
aid  of  a  suitable  barrow  or  truck,  run  them  to  the  slide  which 
takes  them  to  the  dampening  or  storage  room  direct. 

There  is  a  most  economical  elevator  or  lift  which  should 
be  known  to  all  tanners  who  propose  to  adopt  this  turret  dry- 
er. It  consists  of  an  endless  chain  running  from  the  extreme 
bottom  to  the  top  floor,  ending  under  the  roof.  This  chain 
should  run  in  a  wooden  box,  inclosed  on  three  sides.  The 
outward  or  open  side  will  serve  to  attach  the  sides  by  means 
of  hooks  fixed  to  the  links  of  the  chain,  say  at  distances  of 
about  four  feet,  depending  on  the  rapidity  with  which  the 
chain  moves.  The  distances  between  the  attaching  hooks 
should  be  sufficient  to  enable  the  attendants  to  attach  below 
and  take  off  above  the  sides.  By  this  economical  method 
leather  may  be  elevated  to  the  highest  loft  with  no  more 
actual  expense  than  if  dried  on  the  ground  floor,  and  the 
sides,  when  once  hung,  remain  until  fully  dried — thus  saving 
all  expense  of  "  shifting,"  etc. 

"What  has  been  said  in  another  place  upon  the  influence  of 
light  and  heat  upon  color  will  measurably  apply  to  this  pro- 
cess. Leather  dried  in  the  open  air  will  certainly  dry  dark, 
even  if  tanned  with  pure  oak,  and,  if  tanned  with  hemlock 
or  a  mixed  bark,  will  darken  to  a  damaging  extent.  If  cur- 
rents of  air  reach  the  leather  while  in  a  wet  state,  a  like 
result  is  produced,  with  the  addition  of  great  harshness  of 
grain.  If  a  bright  light,  particularly  if  the  sun's  rays  reach 
the  grain  or  flesh,  the  leather  turns  brown,  and  is  perma- 
nently discolored.  The  influence  of  the  direct  sun's  rays,  or 
even  the  strong  light  of  the  sun  on  vegetation,  is  a  good 
illustration  of  such  influences  on  the  color  of  leather  con- 
taining vegetable  acid  in  solution.  The  ordinary  table  celery 
is  covered  with  earth  as  fast  as  it  comes  to  the  surface,  to 
keep  the  light  from  it,  so  that  it  may  be  white  and  tender. 


116  THE  LEATHER  MANUFACTURE. 

Pie  plant  which  grows  under  a  barrel  or  in  the  shade  will  be 
white  and  not  green.  Grass  that  grows  under  cover,  excluded 
from  the  light,  is  white,  not  green.  This  law  of  light  applies 
to  all  vegetation.  Availing  ourselves  of  this  principle,  there- 
fore, we  say  leather  that  is  intended  to  be  fair  in  color  should 
be  dried  in  the  dark,  and  as  free  as  possible  from  currents  of 
air. 

An  illustration  of  the  "  turret"  dryer, with  further  explana- 
tions of  its  construction  and  mode  of  operation,  will  be  found 
in  later  pages. 


CHAPTEE   XIII. 

CONSTRUCTION    OF     TANNEKIES  —  PLANS,    FOUNDA- 
TIONS,   ETC. 

THOROUGH    EXAMINATION    OF   PRESENT   STRUCTURES    AND    APPLIANCES   AD- 
VISABLE BEEORE  BUILDING IMPORTANT    CHANGES  FROM  THE  PRESENT 

GENERAL    USE    OF    STEAM    INSTEAD    OF   WATER   POWER — LOCATING  ON 

"MANUFACTURING"  AND  "CULINARY"  STREAMS — A  LOAM,  CLAY,  OR 
SANDY  FOUNDATION — FILLING  IN  BETWEEN  VATS  AND  LEACHES  WITH 

LOAM  OR   CLAY PLACING   THE   VATS THE    "BUFFALO"  VAT "BOX" 

VATS THE    PROCESS    OF    "PUDDLING"   IN  SETTING   THE   VATS UPPER 

CONDUCTORS SIDE  AND  END  WALLS. 

As  preliminary  to  all  efforts  to  erect  a  tannery,  drawings 
and  working  plans  should  be  fully  prepared.  These  plans 
should  not  be  merely  in  the  mind  of  the  owner  or  builder,  but 
they  should  be  elaborately  placed  on  paper,  so  that  they  can 
be  well  defined  and  susceptible  of  examination  and  discussion. 
The  writer  has  seen  so  many  expensive  failures  by  reason  of 
neglect  in  this  respect,  that,  at  the  risk  of  being  considered 
superserviceable,  he  would  insist  that,  first  of  all,  when  the 
erection  of  a  tannery  is  decided  upon  (and  before  the  plans 
are  drawn),  extensive  visitations  should  be  made  to  the  best 
constructed  tanneries^  where  can  be  seen  in  practical  use  all 
the  best-known  improvements.  The  characteristic  readiness, 
and  even  pleasure,  with  which  American  tanners  .show  their 
works,  and  honestly  discuss  the  merits  of  their  methods, 
leaves  no  excuse  for  any  man  who  proposes  to  erect  a  new 


118  THE  LEATHER  MANUFACTURF. 

yard  not  fo  avail  himself  of  all  the  experience  which  has  been 
obtained  by  others.  On  this  trip  of  observation  both  the 
draftsman  and  the  head  mechanic  should  be  of  the  company, 
and  they  should  not  stop  short  of  visiting  every  tannery  where 
a  new  idea  can  be  obtained. 

Leaving  out  of  view  at  present  the  question  of  location  for 
the  economical  supply  of  bark,  hides  and  other  material,  we 
will  treat  at  present  only  of  the  proper  location  of  the  build- 
ings, irrespective  of  the  markets  for  hides  and  leather,  and 
the  bark  supply. 

Until  within  the  last  ten  or  fifteen  years,  most  of  our  tan- 
neries were  driven  by  water  power,  and  this  fact  caused  the 
buildings  to  be  erected  not  only  on  the  immediate  bank,  but 
usually  the  foundations  were  placed  on  the  bed  of  a  stream. 
This  close  proximity  to  the  water  was  made  necessary  to  en- 
able advantage  to  be  taken  of  the  "  head  and  fall,"  thus  se- 
curing the  greatest  amount  of  power  to  drive  the  machinery. 
Such  locations  have  always  subjected  the  tanner  to'  great 
danger  from  the  overflowing  stream,  and  as  these  risks  were 
not  insurable,  many  men  have  been  entirely  ruined  by  disas- 
trous floods.  But  beyond  these  extraordinary  risks,  such 
locations  were  usually  very  expensive  to  prepare,  since  rocks 
and  boulders  had  to  be  blasted  and  removed,  and  when  this 
was  done  the  foundations  were  often  uneven  and  hard  to  ad- 
just to  the  conductors  and  vats  which  rested  upon  them. 
Since  the  substitution  of  steam  for  water  power,  all  these 
difficulties,  and  many  more  which  might  be  enumerated,  are 
avoided. 

The  tannery  buildings  should  be  located  near  a  capacious 
and  never-failing  stream  of  water.  The  stream  need  not  be 
large,  for  any  direct  purpose  of  the  tannery,  but  a  clear  dis- 
tinction should  be  drawn  between  "  manufacturing "  and 
"  culinary  "  streams,  as  the  health  laws  and  public  policy  of 


THE   LEATHER   MANUFACTURE.  119 

all  civilized  nations  make  a  wide  difference  between  these 
classes  of  water  courses.  If  a  tanner  locates  himself  on  a 
"  culinary  "  stream,  he  is  always  liable  to  the  complaints  of 
his  neighbors  below  him — and  even  on  a  manufacturing 
stream  he  should,  as  far  as  possible,  avoid  throwing  his  waste 
in  the  water  way,  for,  according  to  opinions  of  some  of  our 
courts,  he  is  responsible  for  all  actual  damage  done  even  on 
such  streams.  But  if  a  tannery  is  properly  located  and  con- 
structed, it  will  be  found  profitable  to  retain  and  utilize  all 
refuse  animal  and  even  vegetable  matter,  which  so  defile  the 
stream  when  thrown  in,  and  it  really  seems  to  the  writer  a 
providential  and  happy  influence  which  intervenes  to  prevent 
the  tanner  from  thus  injuring  himself. 

The  location  of  the  tannery  should,  if  practicable,  be  on  a 
loamy,  clay,  or  at  worst  a  sandy  foundation.  If  possible  a 
loamy  foundation  should  be  secured.  Whoever  doubts  that 
loam  is  equal  to  or  even  better,  practically,  than  clay,  should 
try  some  experiments  similar  to  several  which  have  come 
within  my  observation.  Clay,  if  thoroughly  worked,  and 
"rammed"  with  great  care,  will,  beyond  all  doubt,  act  as  a 
good  preservative  of  wood;  but,  by  reason  of  the  great 
amount  of  labor  and  care  required  in  its  manipulation,  it 
often  happens  that  the  material  is  unequally  worked,  and 
spots  of  dry  or  unworked  clay  will  be  thrown  in ;  this  per- 
mits the  access  of  air,  causing  defective  parts  in  the  wood, 
and  soon  the  soundness  of  the  whole  structure  is  destroyed. 
Loam  is  much  easier  worked,  and  defects  in  its  manipulation 
can  hardly  escape  detection.  The  experiment  which  is  com- 
mended to  all  doubters  is  as  follows :  Take  a  common  pail 
and  fill  with  loam,  mixing  and  mingling  water  therewith, 
until  the  whole  mass  is  of  about  the  consistency  of  very  thin 
mortar  ;  then  allow  the  contents  to  settle  for  a  day  or  two,  and 
the  result  will  be  that  the  water  will  stand  on  top  and  the 


120  THE  LEATHER  MANUFACTURE. 

earthy  or  loamy  substance  will  fall  to  the  bottom,  in  such 
order  and  compactness  as  absolutely  to  form  a  sandstone ; 
indeed,  it  is  just  this  process  in  nature  that  forms  the  sand- 
stone which  we  everywhere  see.  When  this  loamy  or  earthy 
substance  has  fairly  settled,  holes  may  be  bored  in  the  bottom 
of  the  pail  and  the  water  will  not  percolate  through,  but  will 
remain  on  top  and  finally  evaporate. 

The  principle  upon  which  this  stone  formation  takes  place 
must  be  observed  in  filling  in  between  vats  or  leaches,  other- 
wise there  will  be  failure.  When  the  whole  mass  is  in  a 
liquid  or  soluble  condition,  and  is  at  rest,  the  settlement 
begins,  according  to  the  law  of  gravitation,  the  denser  or 
heavier  particles  dropping  first,  and  then  the  next  heaviest, 
and  so  on  until  the  whole  body  has  settled  just  in  the  order 
of  the  specific  gravity  of  its  parts. 

Now,  it  must  be  evident  that,  if  the  best  result  would  be 
secured  when  puddling  in  between  the  vats  or  leaches,  the 
whole  mass  should  go  in  together  and  be  plunged  and  mixed 
so  that  this  order  of  settlement  and  adjustment  may  be  the 
resvilt.  When  loam  is  thus  placed  in  between  the  vats  it  is 
almost  impossible  that  there  should  be  any  leak.  The  writer 
has  seen  whole  yards  sunk  without  corking  any  of  the  joints, 
and  yet  all  the  vats  remained  tight. 

When  from  any  cause  the  foundation  is  defective — when 
gravel  or  projecting  rocks  are  likely  to  allow  water  courses 
to  be  formed — the  interstices  must  not  only  be  filled,  but 
made  absolutely  tight,  and  even  new  foundations  must  be 
artificially  formed  with  loam,  to  the  depth  of  one  foot  at 
least  below  the  log  conductors.  If  by  any  chance  a  water 
course  should  be  formed  under  the  yard,  the  entire  profits  of 
the  tanner  may  run  away.  The  tanner  should  remember 
that  for  a  mistake  in  omitting  to  lay  his  foundations  both 
deep  and  water  tight,  he  is  liable  ever  after  to  unconsciously 


THE  LEATHER  MANUFACTURE.  121 

waste  liis  liquors.  "When  it  is  considered  that  they  are  al- 
most as  valuable  as  malt  liquors,  he  will  comprehend  the  im- 
portance of  the  greatest  possible  care.  No  brewer  would 
hazard  the  possibility  of  a  leak  in  his  underground  tanks, 
however  small,  nor  should  a  tanner. 

When  the  foundation  ground  is  thoroughly  prepared  — 
then,  and  not  before,  should  the  log  conductors  be  placed. 
Tlie  vats  may  rest  firmly  on  the  conductors.  The  point  of 
contact  should  of  course  be  at  the  ends,  where  the  tube  con- 
nections are  to  be  made.  But  in  addition  to  the  rest  on 
this  log  conductor,  timbers  at  least  6  by  8  inches  should  be 
thoroughly  imbedded  in  the  loam  formation,  not  more  than 
two  feet  apart,  thus  supporting  the  vats  uniformly  and  equal- 
izing the  strain.  Otherwise  the  vats  will  certainly  leak  after 
a  short  time. 

When  the  conductors  and  supporting  timbers  are  placed 
evenly  over  the  whole  yard  surface,  there  should  be  a  renewed 
attempt  to  puddle  with  a  thin  loam  mixture — so  thin  that 
the  smallest  aperture  or  crevice  underneath  will  be  filled 
effectually. 

At  this  s^age  of  the  construction  there  come  in  at  least  two 
different  kinds  of  vat  builders,  with  their  plans  of  construc- 
tion, both  having  merit.  The  first  plan  is  known  as  the 
"  Buffalo"  method.  This  designation  comes  only  from  the 
fact  that  the  Buffalo  tanners  first  adopted  it.  It  contemplates 
the  foundations  prepared  as  heretofore  indicated ;  upon  these 
foundations,  plank,  which  with  this  plan  should  be  at  least 
three  inches  thick,  are  closely  jointed  and  laid  over  the  whole 
surface,  and  then  spiked  to  the  timbers.  Sometimes  these 
plank  are  tongued  and  grooved,  sometimes  only  jointed  up 
close,  and  when  the  plank  are  half  seasoned  the  joints  may 
be  trusted  to  close  by  the  action  of  the  dampness  swelling 
them  tight ;  but  a  corking  joint,  well  filled  with  oakum,  is,  in 


122  THE  LEATHER  MANUFACTURE. 

my  judgment,  much  the  safest  reliance.  After  the  flooring 
plank  have  thus  all  been  evenly  and  permanently  laid  and 
corked,  the  grooving  plane  cuts  the  grooves,  into  which  the 
planks  of  the  vats  are  inserted  endwise,  so  that,  when  the  vat 
is  formed  by  these  prepared  plank  standing  endwise,  resting 
in  these  close-fitting  grooves,  each  side  and  end  of  the  vat  is 
keyed  up  by  a  "wedge  plank." 

The  only  advantage  that  this  form  of  vat  has  over  what  is 
termed  the  "box"  form  is  that  there  is  no  space  wasted  be- 
tween the  vats,  and,  of  course,  if  leaks  occur,  they  can  only 
be  from  one  vat  to  another.  In  locations  like  our  large  towns 
and  cities,  where  land  is  very  valuable,  this  method  of  con- 
structing vats  has  generally  prevailed,  as  it  saves  at  least 
four  inches  space  between  them.  The  writer  cannot,  how- 
ever, but  think  that,  both  on  the  ground  of  economy  of  con- 
struction as  well  as  safety,  the  box  form  is  to  be  preferred. 

The  ordinary  "battened"  and  "box"  vat  is,  in  my  judg- 
ment, the  best,  because  the  safer  form,  where  lumber  is  cheap 
and  where  space  is  of  no  value,  as  is  generally  the  case  in 
new  territory,  where  our  tanneries  are  -usually  constructed. 
This  form  of  making  the  vats  may  be  thus  described.  After 
the  preparation  of  the  foundations,  as  heretofore  indicated, 
boxes  made  of  plank,  either  two  or  three  inches  thick,  bat- 
tened together,  are  placed  side  by  side  and  end  to  end  over 
the  whole  surface.  The  battens  are  "  dropped  in"  and  "pass 
each  other;"  or,  to  use  the  mechanical  term,  "joints  are 
broken,"  so  that  the  battens  form  supports  to  both  sides  and 
ends  of  the  vats  that  come  into  contact  and  adjoin  each 
other.  "When  thus  placed,  connections  are  made,  by  tubes 
through  the  bottoms,  with  the  log  conductors  beneath,  and 
the  seams  are  thoroughly  corked  with  "  spun  "  oakum.  The 
best  form  of  making  these  seams,  and  the  most  reliable  and 
economical  method  of  making  tube  connections,  it  is  iinpos- 


THE   LEATHER   MANUFACTURE.  123 

sible  in  words  to  communicate,  but  it  may  be  assumed  that 
whoever  really  intends  to  avail  himself  of  these  suggestions 
will  think  it  worth  while  to  investigate  more  fully  before  he 
attempts  to  put  in  practice  ideas  which,  at  best,  are  very 
imperfectly  described  in  these  chapters.  There  are  economic 
methods  of  preparing  the  plank  for  these  vats,  which  have 
been  employed  within  a  few  years,  which  put  to  shame  the 
older  hand  methods.  Whether  the  plank  for  vats  should  be 
made  'of  pine  or  hemlock  timber,  and  whether  from  plank 
two  or  more  inches  in  thickness,  are  matters  of  detail,  which 
it  would  be  foreign  to  the  object  of  this  chapter  to  consider. 

After  these  box  vats  have  been  placed,  corked,  and  the 
proper  tube  connections  made,  then  comes  the  important 
work  of  puddling.  Many  yards  have  been  ruined  for  want 
of  care  in  this  particular.  The  vats  must  be  filled  with  water 
just  as  fast  as,  and  no  faster  than,  they  are  "puddled  in" 
from  the  sides  and  ends.  Some  tanners  think  it  sufficient  to 
hold  the  vats  in  place  by  putting  weights  on  the  top,  or  by 
studding  from  the  floor  upward,  but  neither  of  these  forms 
should  be  relied  upon,  since  the  pressure  of  the  concrete,  or 
puddling,  from  below,  is  very  great,  and  it  should  be  met  by 
an  equal,  uniform,  downward  pressure — such  as  only  the 
weight  of  the  water  filling  can  give.  The  loam  which  is 
used  to  fill  in  between  the  vats  should  be  placed  convenient 
to  the  yard,  should  be  prepared  in  tight  mortar  boxes  before 
it  is  run  in,  and  fo  thoroughly  mixed  that  it  will  run  in  box 
shutes  to  any  desired  spot.  Carrying  in  pails,  or  otherwise 
handling,  makes  slow  work,  and  too  often  induces  the  throw- 
ing in  of  the  dry  loam  and  the  attempt  to  mix  by  plunging. 
This  form  leads  to  air  holes  and  imperfect  puddling.  The 
whole  process  should  be  carried  through  on  a  uniform  sys- 
tem, and  no  slighting  or  imperfect  work  should  be  permitted. 

Mr.  James  Clewer,  who  was  the  author  of  this  system, 


124  THE  LEATHER  MANUFACTURE. 

always  claimed  that  it  was  possible  to  so  perfectly  puddle 
vats  with  loam  as  to  render  corking  unnecessary.  Indeed, 
he  did  establish  two  or  three  yards  on  this  plan  without  any 
corking  whatever,  and  to  this  day  (now  more  than  thirty 
years  afterward)  the  yards  do  not  leak  outwardly,  though 
some  of  the  seams  leak  inwardly — that  is,  the  drip  and  drain- 
ing of  the  loam  finds  its  way  through  the  seams,  and  dis- 
colors slightly,  but  only  occasionally,  the  sides  that  come  in 
contact  with  it. 

By  omitting  the  precaution  of  filling  the  vats  with  water 
before  puddling,  the  result  will  be  not  only  that  the  vats  will 
be  raised  from  their  foundations,  thereby  disturbing  the 
tube  connections,  but  the  sides  and  ends  will  be  forced  in- 
wardly, so  that  ever  after  the  shape  of  the  vats  will  be  dis- 
torted and  their  capacity  lessened. 

The  "caps"  or  alley  flooring  resting  on  the  tops  of  the 
vats  should  be  often  raised  to  see  that  the  filling  has  not 
given  way.  If,  as  is  quite  likely  for  the  first  few  months, 
such  giving  way  or  sinking  is  noticed,  great  care  should  be 
observed  in  refilling.  When  once  the  loam  has  thoroughly 
settled  and  become  fixed  in  place,  it  may  be  considered  cer- 
tain that  a  perfectly  tight  yard  is  guaranteed  for  all  time. 

Some  tanners  have  an  upper  system  of  conductors  through 
which  they  supply  their  vats  with  new  and  strong  liquors. 
These,  when  new  and  perfect,  are  very  convenient,  but  such 
conductors  are  not  to  be  trusted.  After  a  few  years  they  be- 
come decayed  and  leak,  to  the  great  damage  and  waste  of  the 
liquor.  No  care  in  the  placing  seems  adequate  to  keep  the 
air  from  these  wooden  structures  when  made  so  near  the  sur- 
face, and  when  the  air  does  reach  the  wood  it  is  certain  to 
rot  it  in  four  or  five  years.  It  is  for  this  reason  the  use  of 
these  upper  conductors  between  the  vats  cannot  be  recom- 
mended, even  where  they  are  partially  covered  with  earth. 


THE  LEATHER  MANUFACTURE.  125 

It  is  far  better  to  have  the  upper  conductors  wholly  above 
the  top  of  the  yard,  either  in  open  shutes  or  in  tight  log  con- 
ductors, where  any  leak  can  be  detected. 

"When  a  tannery  is  located  on  an  earth  foundation,  the  side 
and  end  walls  need  not  be  extended  to  the  lower  foundations. 
Excavations  can  be  made,  the  yard  placed  and  filled  in,  and 
side  and  end  walls  may  be  commenced  on  timbers  laid  within 
two  or  three  feet  of  the  surface.  If  the  timber  is  laid  below 
the  frost,  and  below  the  point  reached  by  the  air,  it  will  last 
forever,  and  it  will  be  safe  to  lay  a  brick,  stone  or  concrete 
wall  from  this  timber  foundation  upward,  say  two  or  three 
feet  above  the  surface  of  the  ground,  on  which  the  sills  of  the 
building  may  finally  rest,  beyond  the  reach  of  the  damp 
earth  beneath.  If  the  filling  in  on  the  outside  of  the  vats 
has  been  thoroughly  done,  this  filling  gives  a  more  secure 
foundation  than  the  natural  earth,  and  will  save  much  ex- 
pense in  the  foundations. 

If  it  is  thought  desirable,  as  it  is  in  the  opinion  of  most 
tanners,  to  erect  the  frame  before  setting  the  vats,  the  frame 
can  be  supported  by  temporary  posts,  running  down  to  the 
foundation,  and  the  making  of  a  more  permanent  foundation 
may  safely  be  left  tDl  the  filling  in  is  done,  as  here  indicated. 
It  will  be  useful  for  all  tanners  to  remember  that  hemlock 
is  just  as  lasting  under  ground  as  pine  or  other  wood. 


CHAPTEE    XIY. 
CONSTRUCTION  OF  TANNERIES— LEACHES. 

BOUND  OB  SQUAKE  LEACHES THE  DURATION  OF  LEACHES  ABOVE  AND  SUNK 

IN  THE  GROUND HOW  TO  BUILD  A  ROUND  LEACH HOW  TO  MAKE 

AND  SET  LEACHES  IN  THE  GROUND THE  CAPACITY  OF  THE  SETS  OF 

LEACHES  TO  BE  PROPORTIONED  TO  THE  SIZE  OF  THE  TANNERY. 

The  form  and  construction  of  leaches  is  a  problem  of 
great  importance  to  tanners.  Shall  they  be  round  or  square  ? 
Shall  they  be  above  or  underground  ?  Shall  they  be  con- 
structed of  wood,  stone,  or  brick,  and,  if  the  former,  then 
shall  oak,  hemlock  or  pine  be  used  ?  How  can  they  be  most 
economically  constructed  ?  How  long  will  they  last  made  of 
either  of  the  materials  or  forms  named  ?  AH  these  questions, 
and  others  besides,  will  occur  to  the  practical  tanner  who 
contemplates  building  a  tannery ;  they  are  included  in  the 
general  question,  "What  kind  of  leaches  are  the  most  econom- 
ical for  tanners'  use  ? 

Since  the  introduction  of  the  "  sprinkler  leach  "  most  tan- 
ners have  made  their  leaches  round.  It  is  quite  a  mistake  to 
suppose  that  the  patented  improvement  covers  the  use  of  any 
kind  of  a  round  leach.  It  is  true,  probably,  that  a  round 
leach  is  better  adapted  to  the  "  sprinkler "  than  any  other 
form,  and  for  this  reason  the  patentees  have  adopted  it. 
There  certainly  is  nothing  novel  in  this  form  since,  on  the 


THE  LEATHER  MANUFACTURE.  127 

Continent  of  Europe,  all  tanners  use  round  vats,  and  leaches, 
too,  whenever  they  use  leaches  at  all.  If,  therefore,  tanners 
conclude  that  round  leaches  are  preferable  to  square  ones, 
they  are  quite  at  liberty  to  use  them  without  any  patent 
claim. 

It  is  safe  to  assume  that  no  leach  made  of  wood,  however 
constructed,  will,  if  placed  above  ground,  where  air  has 
access  to  it,  last  more  than  four  or  five  years  ;  by  that  time 
leaks  will  become  so  plenty  as  to  necessitate  a  renewal.  It 
is  said  of  a  chain  that  the  whole  is  no  stronger  than  its 
weakest  link ;  so  it  may  be  said  of  a  wooden  tank  or  leach — 
the  whole  is  no  more  lasting  than  its  most  imperfect  stave  or 
joint.  Practically,  then,  whenever  a  single  defect  occurs  the 
whole  leach  must  be  abandoned.  It  would  never  be  wise  to 
put  new  staves  in  a  defective  leach,  anymore  than  the  house- 
wife would  think  of  mending  an  old  water-pail  by  replacing 
a  defective  chime. 

In  considering,  then,  the  economy  of  round  leaches  placed 
above  ground,  we  are  to  estimate  the  duration  of  one  of  these 
structures  by  its  single  parts,  and  not  by  its  whole  structure. 
The  experience  of  the  most  successful  tanner  using  these 
round  leaches  above  ground  will  show  that  four,  or  at  most 
five,  years  is  the  duration  or  life  of  one  of  these  structures. 
Reference  is  here  made  to  the  tight  round  leach — a  leach  that 
can  safely  stand  full  of  strong  liquor  without  "  receiving 
leaches"  or  " drips"  standing  underneath,  for  in  this  manner 
these  leaches  have  always  been  constructed  and  worked. 
But  if  a  tight  plank  flooring  should  be  constructed,  and  the 
leaches  placed  above  it,  the  writer  never  could  understand 
why  attention  should  be  paid  to  a  small  leak ;  indeed,  if  the 
leach  was  never  filled  with  liquor,  why  should  there  be  any 
pressure  on  the  joints  ?  Why  should  there  be  any  leak,  or  if 
there  was,  why  should  any  loss  or  injury  result?  This  as- 


128  THE   LEATHEK  MANUFACTURE. 

sunies  that  the  bark  is  percolated  by  the  liquor  as  fast  as  tho 
latter  passes  the  sprinkler;  that  the  liquor  never  floods  the 
bark — and,  so  far  as  the  principle  of  the  patented  improve- 
ment is  concerned,  this  form  of  operation  would  more  fully 
answer  the  purposes  of  the  patent  than  if  a  portion  of  the 
bark  was  flooded — that  is,  had  standing  liquor  in  the  leach. 
Indeed,  just  to  the  extent  that  liquor  stands  in  the  leach  the 
patented  idea  is  lost  sight  of.  It  then  becomes  a  press, 
rather  than  a  percolating  or  sprinkler  leach.  The  form  of 
running  these  leaches  should  properly  influence  their  con- 
struction, for  there  is  no  reason  why  a  sprinkler  leach,  run 
upon  the  true  principles  of  the  patent,  should  ever  rot  or 
wear  out,  since,  so  long  as  the  staves  stand  up  or  the  bottom 
remains  in,  it  will  inclose  and  hold  bark ;  and,  so  long  as  the 
staves  would  hold  together  to  guide  and  confine  the  liquor  in 
its  downward  course,  a  sprinkler  leach  would  still  remain  to 
perform  its  office.  Of  course  this  defective  structure  would 
necessitate  a  tight  plank  flooring  beneath  ;  but,  so  far  as  the 
writer  is  informed,  the  patentee  has  never  recommended  this 
form  of  handling  these  leaches,  and  until  he  does  we  must 
treat  them  as  tight  leaches,  and  subject  to  be  renewed  once 
in  four  or  five  years,  under  the  most  favorable  circumstances, 
when  they  stand  above  ground. 

In  deciding  upon  the  material  to  be  used  in  building 
leaches,  it  should  be  understood  that  young,  sound  hem- 
lock is  just  as  likely  to  last  the  allotted  time  as  the  best 
pine ;  but  care  should  be  taken  to  have  the  staves  made  from 
uniformly  young  trees,  perfectly  sound  and  fresh — -that  is, 
just  peeled  and  sawed,  and  not  from  either  old  timber  or  that 
which  has  been  lying  two  or  three  years  before  being  sawed. 
Young  hemlock  trees,  say  not  more  than  one  foot  in  diameter, 
sawed  into  staves  six  inches  wide  and  two  inches  thick,  can 
be  manufactured  into  tank  or  leach  staves  almost  as  fast  as 


THE   LEATHER   MANUFACTURE.  129 

they  can  be  picked  up  and  passed  twice  through  the  hands 
of  the  employe. 

The  writer  gives  a  little  detailed  instruction  upon  this 
point,  since,  through  unreflecting  employes,  he  was  once 
made  to  suffer  many  thousands  of  dollars'  loss  for  the  want 
of  a  proper  knowledge  of  the  economies  of  this  subject. 
After  the  plank  have  been  sawed  of  the  requisite  length  and 
width — usually  seven  feet  long  and  six  inches  wide — the 
staves  in  this  rough  form  are  beveled  by  a  circular  saw  on 
both  edges.  This  bevel,  of  course,  is  made  to  adjust  to  a 
circle  of  8,  12  or  1G  feet,  depending  upon  the  diameter  of  the 
leach.  When  the  staves  are  thus  uniformly  beveled,  they 
are  laid  in  a  circular  form,  ten  or  fifteen  at  a  time,  and  are 
chimed  out  by  a  "  chiming"  or  "  grooving  plane."  After  be- 
ing thus  formed  they  can  be  set  up  around  the  round  bot- 
tom into  which  they  are  driven,  and  where  they  are  held  to- 
gether by  iron  hoops,  without  calking;  such  a  leach  will 
certainly  be  tight. 

The  saw  that  makes  the  bevels  should  be  about  eight 
inches  in  diameter,  and  be  very  straight,  fine  and  even  in  its 
set,  so  that  a  perfectly  uniform  surface  may  be  secured.  It  is 
said  "uniform,"  rather  than  "smooth,"  because  it  has  been 
often  demonstrated  that  such  a  surface,  when  pressed  to- 
gether will  form  a  tighter  joint  than  can  be  secured  by  the 
hand  plane,  however  much  pains  may  be  taken  to  secure 
smoothness.  Very  great  attention  should  be  paid  to  the 
character  of  the  material.  Hemlock  is  so  cheap  and  abund- 
ant that  none  need  be  taken  that  is  not  perfect,  both  as  to 
soundness  and  uniformity  of  thickness. 

In  making  the  bottom  of  the  leach,  hemlock  plank,  plump 
two  inches  thick,  should  be  used  if  the  leach  is  to  be  eight  or 
twelve  feet  in  diameter,  and  if  it  is  to  be  sixteen  feet  in  di- 
ameter then  the  plank  should  be  three  inches,  in  thickness ; 


330  THE  LEATHEE  MANUFACTURE. 

in  both  cases  the  edges  should  be  chamfered  down  to  a  uni- 
form thickness  of  two  inches  "  scant."  On  the  supposition 
that  the  leach  is  to  be  made  twelve  feet  in  diameter,  the 
plank  may  be  sawed  sixteen  feet  long,  whgn  they  will  cut  into 
bottom  plank  to  good  advantage.  But  it  is  seldom  worth 
while  to  attempt  to  economize  so  closely  as  to  save  the  whole 
of  hemlock  timber,  and  therefore,  at  the  expense  of  a  little 
possible  waste,  only  perfect  plank  should  be  used  in  the  bot- 
tom. These,  after  being  square-edged  with  a  small  fine-set 
circular  saw,  should  be  laid  down  on  a  platform  bench,  and 
firmly  griped  together,  secured  by  a  temporary  batten ;  when 
thus  placed  a  circle  should  be  inscribed  the  size  of  the  pro- 
posed leach.  With  a  small  whip  saw  this  line  should  be  very 
carefully  followed,  taking  great  care  to  make  the  cut  square, 
and  at  a  right  angle  with  the  surface  of  the  plank.  If  this  is 
done  with  care  and  with  a  suitably  straight  saw,  there  need 
be  but  little  after-work  with  the  plane  to  make  the  circle 
smooth  and  otherwise  perfect.  If  care  has  also  been  taken 
to  have  the  plank  originally  sawed  of  uniform  thickness,  a 
very  little  work  with  the  plane  will  bring  the  edges  to  a  uni- 
form thickness,  so  that  when  put  together  the  outer  rim  of 
the  bottom  will  exactly  fill  and  fit  the  chime  groove  in  the 
stave,  making  a  reasonably  good,  tight  j  >int. 

We  are  now  ready  to  set  up  our  leach,  and  we  want  round 
hoops  of  at  least  five-eighths  or  three-quarters  irom.  The 
lengths  should,  as  far  as  possible,  be  purchased  to  suit  the 
size  of  the  leach.  Usually  this  round  iron  comes  twelve  feet 
long,  but  it  may  be  obtained  of  any  length  desired.  There 
should  be  but  one  joint  for  each  hoop — a  sufficient  length  of 
iron  being  welded  together  to  go  completely  round  the  leach 
—and  the  ends  should  come  together  in  a  cotterel,  which 
may  be  of  cast  iron  or  hard  wood.  If  one  of  the  ends  of 
the  iron  should  have  a  screw  cut  on  it  for  six  inches,  while 


THE   LEATHER   MANUFACTURE.  131 

the  other  is  firmly  fastened  in  the  cotterel,  a  nut  and  wrench 
will  draw  the  hoop  as  tight  as  it  could  be  driven,  if  the  form 
of  the  leach  was  tapering  in  shape,  as  on  a  pail  or  ordinary 
wash  tub ;  but  as  it  is  desirable  to  have  these  leaches  of  uni- 
form diameter,  this  form  of  drawing  together  and  holding  the 
stave  must  be  resorted  to. 

There  is  nothing  difficult  or  expensive  in  constructing  this 
form  of  leach,  if  the  proper  skill  and  machinery  are  at  hand, 
but  without  this  machinery  and  this  knowledge  they  are  very 
expensive,  and  often  fail  of  being  tight.  With  the  small  saw 
and  mandrel,  which  cost  about  thirty  dollars,  and  a  chiming 
plane,  which  will  cost  about  eight  dollars,  these  round  leaches 
may  be  put  together  with  ordinary  carpenters'  tools  at  a  very 
inconsiderable  cost.  The  cost  of  the  labor  need  not  be  over 
ten  dollars  for  an  ordinary  leach,  twelve  feet  in  diameter,  and 
seven  feet  deep  in  the  clear.  The  expense  may  be  increased 
by  a  greater  regard  for  permanency  in  its  construction,  as 
the  material  may  be  clear  pine  or  oak,  the  hoops  may  be  of 
heavier  iron,  and  instead  of  four  hoops  (the  usual  number) 
there  may  be  six.  But  in  this,  as  in  all  tannery  construction, 
as  much  simplicity  and  cheapness  should  be  observed  as  is 
compatible  with  the  service  to  be  performed.  The  iron  hoops 
used  will  last  during  the  lifetime  of  several  wooden  struc- 
tures. On  the  whole  there  can  be  no  doubt  that  round 
leaches,  constructed  as  here  suggested,  should  always  be 
employed  when  the  leaches  are  to  be  used  above  ground ; 
but  for  underground  leaches,  or  leaches  filled  in  with  earth, 
quite  a  different  construction  is  suggested. 

Until  the  introduction  of  the  Allen  &  Warren  sprinkler 
leach,  square  leaches  set  in  the  ground,  in  a  packing  of  loam 
or  clay,  were  in  general  use,  and  to-day  are  not  abandoned 
even  by  our  best  tanners.  A  set  of  these  leaches,  properly 
placed  and  filled  in,  will  last  for  twenty  or  thirty  years ;  in- 


132  THE   LEATHER   MANUFACTURE. 

deed,  with  slight  repairs  to  the  top  planks,  they  will  last  dur- 
ing the  lifetime  of  a  tannery.  The  writer  knows  of  several 
sets  that  are  now  in  good  order  that  have,  with  slight  repairs, 
been  in  active  use  for  more  than  a  quarter  of  a  century. 

The  preparation  of  the  ground  on  which  these  leaches 
stand  should  be  made  with  even  more  thoroughness,  if  pos- 
sible, than  that  of  the  yard  itself,  since  there  is  more  weight 
resting  on  it,  and  more  disturbance  from  the  flow  of  currents 
of  water.  If  the  leaches  are  constructed  with  proper  open- 
ings in  the  bottom,  through  which  the  spent  tan  is  washed 
after  the  leaching  process  is  over,  then  more  than  ordinary 
care  should  be  observed  in  placing  the  under  conductors, 
otherwise  air  will  reach  the  plank  flooring  and  cause  it  to 
decay.  In  all  locations  where  a  flow  of  water  can  be  secured 
on  the  top  of  the  leaches,  provision  should  be  made  for  this 
to  wash  out  such  portion  of  the  spent  tan  as  may  not  be 
wanted  for  the  furnaces.  Sometimes,  however,  the  nature  of 
the  stream  is  such  that  tanners  are  not  permitted  to  throw 
their  refuse  tan  in  the  water  way,  and  in  such  cases  this 
economical  arrangement  cannot  be  availed  of. 

Ordinarily  these  square  sunken  leaches  are  of  10  by  12,  12 
by  14,  or,  in  exceptional  cases,  16  by  20  feet,  surface  meas- 
urement, and  usually  about  seven  feet  deep.  If  the  leaches 
are  of  the  smaller  sizes,  then  planks  two  inches  thick  are 
quite  sufficient ;  but  if  the  larger  size,  then  planks  at  least 
three  inches  thick  should  be  used ;  not  more,  however,  for 
the  economical  reason  than  from  the  fact  that  the  press  can 
be  better  controlled  in  the  smaller  sizes,  does  the  writer 
commend  this  form  of  leach.  Indeed,  the  number  and  size 
of  leaches  should  correspond  to  the  size  of  the  vats  in  the 
yard.  The  covering  of  one  leach  of  bark  should  make  one 
vat  of  liquor.  There  should  certainly  be  no  fractions.  It 
should  either  be  one,  two,  three  or  four  vats  of  liquor.  At- 


THE   LEATHER  MANUFACTURE.  133 

tention  to  this  seeming  detail  will  much  simplify  the  manipu- 
lations afterward. 

The  preparation  of  the  plank  for  these  leaches  can  be 
made  by  the  same  saw  and  mandrel  which  has  been  com- 
mended for  the  round  leaches ;  even  the  calking  seam  can 
be  formed  with  this  saw.  No  joint  can  be  made  with  a  hand 
plane  that  will  hold  oakum  so  firmly  as  with  this  saw  joint, 
and  the  oakum  joint  is  made  much  truer  by  the  saw  than  it 
can  be  made  with  hand  labor. 

When  the  ends,  sides  and  bottoms  have  been  battened 
properly,  they  are  put  together  as  in  the  case  of  the  vats  de- 
scribed in  a  previous  article.  Indeed,  these  leaches  are  but 
so  many  vats  enlarged  in  size. 

In  Great  Britain  the  tanners  make  use  very  largely  of 
brick  and  cement  to  form  their  vats  and  leaches.  No  doubt 
these  materials  make  a  very  substantial  structure,  and  as 
erected  there,  in  cities  and  towns,  and  intended  to  last  for 
all  time,  this  construction  may  be  the  best.  But  some  at- 
tempts made  in  this  country  to  use  this  material  have  resulted 
in  staining  the  leather.  Whether  this  difficulty  could  not  be 
overcome  with  us,  as  the  English  tanners  claim  it  is  with 
them,  it  seems  hardly  worth  while  to  consider,  since  timber 
is  so  much  cheaper  here  than  brick,  particularly  in  the 
country,  where  all  our  tanneries  are  built.  Wood  plank  will 
last  fifty  years,  sunk  in  our  usual  way,  and  that  is  quite  as 
long  as  our  civilization  will  tolerate  the  existence  of  a  tan- 
nery in  one  location. 


CHAPTEE    XV. 

CONSTEUCTION   OF   TANNERIES— FEAME  WOEK   AND 
LOCATION  OF  BUILDINGS. 

WHY  THEY  SHOULD  BE  ONLY  ONE-STORY  HIGH  FOR  THE  YARD  AND  BEAM 
HOUSE SAVING  IN  INSURANCE  BY  SEPARATING  THE  BUILDINGS CON- 
VEYING LEATHER  TO  THE  "TURRET"  DRYER TRANSMITTING  POWER 

TO  DISTANT  BUILDINGS PROPER  SPEED  FOR  BARK  MILLS  AND  ELEVA- 
TORS  SIMPLE  PROVISIONS  AGAINST  FIRE  AND  BREAKAGE,  AND  TO  PRE- 
VENT DUST. 

A  modern  tannery  is  quite  a  different  affair  from  one  of  the 
early  Greene  County  (N.  Y.)  structures.  The  various  im- 
proved methods  of  heating  and  obtaining  power  have  ren- 
dered it  quite  unnecessary  to  crowd  into  one  building,  as 
formerly,  bark  mills,  rollers,  hide  mills,  drying  lofts,  yard, 
beam  house,  sweat  pit,  etc.  Heat  and  power  can  now  be 
used  without  limit,  and  wherever  their  use  can  be  made  to 
economize  labor  or  cheapen  insurance  they  should  be  em- 
ployed. 

That  great  advantages  are  secured  by  a  one-story  structure 
over  the  yard  and  beam  house  will  be  conceded  when  the 
following  points  are  considered  : 

1.  The  timber  need  only  be  heavy  enough  to  carry  and 
uphold  the  roof,  not  forgetting,  of  course,  its  probable  load 
of  snow  in  winter. 

2.  No  apprehension  need  be  felt  about  the  falling  in  of  the 
structure  for  a  long  time  after  the  usual  decay  of  the  timbers 


THE   LEATHER   MANUFACTURE.  135 

commences,  since 'they  can  be  replaced  without  inconvenience, 
there  being  no  heavy  superstructure  to  sustain,  whereas  a 
building  with  lofts  above,  often  filled  with  wet  leather,  is  al- 
ways an  object  of  solicitude  to  the  tanner ;  he  is  constantly 
studding  up  and  "supporting"  the  building  to  make  it  safe 
for  the  workmen.  Besides,  these  high  structures  are  subject 
to  the  action  of  the  wind,  which  much  weakens  their  joints 
and  fastenings. 

3.  The  insurance  is  only  one  half  the  price  of  what  was 
paid  on  the  old  and  high  buildings.     Although  these  one- 
story  structures  have  now  been  in  use  for  ten  years  or  more, 
several  hundred  of  them  being  in  existence,  not  a  single  one 
has  yet  been  destroyed  by  fire,  and  if  this  record  shall  not  be 
changed  by  further  experience,  we  may  reasonably  expect  a 
still  further  reduction  in  the  rate  of  insurance.     In  fact,  with 
an  abundant  water  supply  and  efficient  service,  a  one-story 
tannery  cannot  be  wholly  destroyed,  for  nothing  but  the  roof 
could  burn,  and  as  this  can  be  reached  from  both  above  and 
below  with  ordinary  water  buckets,  the  progress  of  the  flames 
can  be  stayed  in  almost  any  case  of  fire  likely  to  happen.     Be- 
sides, the  condensation  of  water  from  the  steam  of  the  yard 
always  keeps  the  roof  boards  and  covering  water  soaked,  so 
that  fire  would  not  spread  rapidly,  if  at  all. 

4.  A  building  of  one  story  for  the  yard  gives  opportunity 
for  a  high  ceiling  and  good  ventilation.     It  has,  however,  this 
single  disadvantage — that  in  winter  it  is  much  more  exposed 
to  the  frost,  although,  practically,  ice  seldom  forms  in  a  yard 
of  this  construction.     Indeed,  experience  has  shown  that  with 
a  few  coils  of  steam  pipe  running  around  above  the  sills  there 
need  be  no  cold  fingers  of  the  workmen.     This  one-stoiy 
structure  should  have  a  flat  roof  (one  foot  pitch  in  ten)  cov- 
ered first  with   boards  and  then  with   asphalt  paper   and 
gravel,  by  a  process  universally  in  use. 


136  THE  LEATHER  MANUFACTURE. 

So  far,  then,  as  the  yard  and  beam  house  are  concerned,  a 
one-story  building  is  the  most  suitable  structure.  But  how 
shall  the  tanned  packs  be  got  to  the  drying  loft?  Heretofore 
trap  doors  have  been  placed  in  each  bent  of  the  building,  so 
that  little  more  was  needed  than  to  open  the  trap  and  hook 
the  sides  from  the  yard  below,  and  thus  pass  them  up  by 
hand  from  loft  to  loft.  This  seeming  convenience  prevented 
any  change  from  the  old  method  for  many  years.  Tanners 
not  unnaturally  reasoned  in  this  way:  "We  have  a  }^ard 
and  beam  house,  and  they  must  be  covered  with  a  roof ;  the 
same  roof  can  equally  cover  our  drying  lofts,  and  as  our  dry- 
ing lofts  must  have  a  capacity  as  large  as  our  whole  beam 
house  and  yard,  in  order  to  dry  our  stock,  why  should  we 
not  make  our  structure  strong  enough  to  carry  all  this  under 
one  roof?"  Besides,  they  have  reasoned:  "Our  insurance 
covers  our  stock  in  both  yard  and  loft,  and  at  the  same  price ; 
why  should  we  go  to  the  expense  of  erecting  a  separate  struc- 
ture, where  our  insurance  would  be  divided,  without  any  com- 
pensating advantages  in  the  way  of  reduction  of  rates?" 
Thus  reasoning,  our  tanners  went  on  from  year  to  year  erect- 
ing new  yards  under  former  plans,  until  within  the  past  ten 
years,  during  which  many  have  been  induced  to  break  away 
from  this  old  method,  and  are  now  building  turret  dryers  in 
connection  with  the  rolling  or  finishing  lofts,  connecting  these 
with  the  yard  by  tramways,  hung  from  above  in  some  in- 
stances, and  in  others  with  bottom  rails  of  wood,  these  tram- 
ways running  cars  through  the  center  of  the  yard,  extending 
out  to  the  drying  lofts.  The  form  of  erecting  these  tramways 
varies  with  each  location.  Where  a  tannery  is  situated  on 
level  ground,  accessible  on,  all  sides  by  a  horse  and  truck, 
probably  there  is  not  a  more  economical  way  of  transferring 
the  wet  stock  from  the  yard  than  by  this  means.  In  this 
case  the  tanner  can  have  openings  from  his  yard  at  fre- 


THE   LEATHER   MANUFACTURE.  137 

quent  intervals,  and  the  nearness  and  saying  of  transporta- 
tion of  the  wet  leather  in  the  yard  will  compensate  for  the 
cost  of  the  service  of  the  horse  and  cart,  over  and  above  a 
tramway  through  the  center  of  the  yard,  to  which  all  tanned 
packs  must  be  brought. 

The  latest  and  most  approved  method  of  locating  the 
buildings  so  entirely  separates  the  yard  from  the  drying  lofts 
that  the  fire  risks  are  greatly  reduced,  for  the  yard  and  beam 
house  are  one  risk,  the  leaches  and  bark  mill  another,  and 
the  furnaces  and  boilers  still  another.  The  building  contain- 
ing the  latter  should  be  placed  at  least  100  feet  from  all  other 
structures,  and  in  itself  made  perfectly  fireproof — that  is, 
there  should  be  no  wood  anywhere  near  the  structure  con- 
taining the  furnaces  and  boilers.  So  arranged,  it  is  found 
practicable  to  run  steam  power  off  in  any  direction  and  al- 
most to  any  distance.  The  most  economical  way  of  running 
off  this  power  is  by  means  of  steam  pipe,  thoroughly  pro- 
tected with  ashes,  loam  or  clay,  well  packed  in  a  box  sur- 
rounding and  inclosing  the  steam  pipe.  The  engines  that 
drive  the  machinery  may  be  in  distant  buildings.  Some  tan- 
ners drive  their  machinery  at  a  distance  of  from  300  to  1,000 
feet  from  the  boilers,  and  the  condensation  does  not  seriously 
affect  the  power,  a  portion  of  which  is  necessarily  lost,  but 
when  wet  spent  tan  is  burned  this  loss  has  no  commercial 
value. 

It  has  been  demonstrated  that  steam  power  can  be  con- 
veyed in  pipes  more  economically  than  by  running  shafting  ; 
that  is,  wherever  power  is  required  a  steam  engine  should  be 
placed  and  steam  conveyed  to  it,  rather  than  to  depend  on 
one  central  engine,  and  either  "  belt "  or  "  shaft "  off.  Engines 
are  now  constructed  so  strong  and  cheap,  and  to  run  with  so 
little  attention,  that  one  engineer  can  take  care  of  two  or  three 
with  the  same  facility  as  one.  The  steam  valves  are  opened 


138  THE  LEATHER  MANUFACTUBE. 

in  tlie  morning,  and  are  not  shut  or  otherwise  disturbed  until 
noon,  and  then  again  are  opened  at  1  p.  M.,  and  not  closed  until 
sundown.  So  different  is  this  practice  from  the  old  method, 
and  the  care  made  necessary  by  the  defective  character  of 
steam  engines,  as  formerly  constructed,  that  engines  may 
now  be  multiplied  to  any  required  extent  without  making  it 
necessary  to  employ  an  assistant  engineer. 

It  may  be  safely  estimated  that  a  one-story  yard  and  beam 
house,  isolated  at  least  100  feet,  can  be  insured  for  1J  per 
cent.,  while  3  and  even  4  per  cent,  is  now  charged  on  ordi- 
nary tanneries  constructed  after  the  old  methods ;  but  no  in- 
surance is  needed  on  the  leather  in  the  vats,  for  neither  the 
leather  nor  the  vats  themselves  will  burn,  evsn  if  the  frame- 
work above  is  destroyed. 

The  turret  drying  loft  (of  which  mention  has  been  suffi- 
ciently made  in  a  previous  chapter)  should  be  near  the  yard, 
and  should  be  classed  in  the  same  risk ;  but  the  leach  house 
and  bark  mills  should  be  in  an  opposite  direction,  and  as  far 
as  possible  from  the  central  or  boiler  house  and  furnaces. 
Where  the  ground  will  permit,  the  boilers  and  furnaces 
should  be  in  the  center,  the  leach  house  and  bark  mills  fully 
one  hundred  feet  to  one  side,  and  the  yard  and  turret  drying 
lofts  as  great  a  distance  in  the  opposite  direction.  This  will 
bring  the  important  structures  two  hundred  feet  apart,  and 
if  the  boiler  and  furnace  building  is  built  as  it  should  be,  of 
stone  or  brick,  and  is  not  over  fifteen  or  twenty  feet  high, 
there  is  really  an  unobstructed  space  of  two  hundred  feet  be- 
tween the  main  fire  risks.  There  is  really  no  manufacturing 
structure  in  the  country  so  free  from  accidents  by  fire,  when 
thus  constructed  and  situated,  as  one  of  these  one-story  yards 
and  beam  houses ;  and  the  drying  lofts,  always  filled  in  part 
with  wet  or  only  partially  dry  leather,  have  a  moist  or  damp 
atmosphere  which,  with  steam  pipe  only  used  as  heaters. 


THE   LEATHER  MANUFACTURE.  139 

renders  anything  like  accident  from  fire  almost  impossible. 
The  natural,  and,  indeed,  the  only  fire  risk  about  a  tannery, 
comes  from  the  bark  mills  and  bark  elevators,  and  in  a  vast 
majority  of  cases  the  fires  which  consume  so  many  tanneries 
proceed  f i  om  this  source.  How  can  this  risk  be  lessened  or 
altogether  avoided?  The  bark  mills  and  elevators  should 
have  a  slow  motion.  No  mill  should  run  above  sixty  to 
eighty  revolutions  per  minute,  and  the  elevator  belt  should 
run  slow  enough  to  enable  the  eye  to  take  in  and  count  the 
buckets  or  boxes  as  they  pass  a  given  point.  The  shovers 
and  screen  should  move  slowly,  for  besides  the  friction  which 
causes  fires  there  is  much  more  wear  and  tear  to  a  quick 
than  to  a  slow  motion,  and  power  is  also  lost. 

An  improvement  has  of  late  been  suggested  to  suppress 
the  dust  arising  from  the  fine  ground  bark,  as  follows :  A 
steam  pipe,  half  an  inch  in  diameter,  connected  with  the 
nearest  direct  pipe  from  the  boiler,  is  brought  to  the  under- 
side of  the  mill ;  a  very  small  jet  of  steam  is  allowed  to  es- 
cape, to  dampen  by  condensation  the  bark  as  it  comes  from 
the  lower  throat  of  the  mill,  and  before  it  drops  into  the  con- 
veyers. This  steam  pipe  could  be  so  placed  that  if  fire 
should  occur  in  the  elevators,  from  friction  or  otherwise,  a 
full  head  could  be  turned  on  by  the  attendant,  and  steam 
forced  upward  through  the  entire  length  of  the  elevator  box. 
This,  therefore,  may  be  regarded  as  an  inexpensive  conjriv- 
ance  to  prevent  dust,  and  also  as  a  great  safeguard  against 
fire;  and  now  that  steam  is  so  cheap  and  abundant  there 
seems  no  reason  why  it  should  not  be  adopted  by  all  tan- 
ners, especially  as  it  is  regarded  by  insurance  companies 
with  great  favor.  Bark  elevators  are  liable  to  get  choked 
and  stop;  when  this  occurs  the  bark  accumulates  and  gets 
packed  in  the  lower  part  of  the  mill ;  great  friction  and  dan- 
ger from  fire  arises  from  this  source,  and  to  avoid  the  dancer 


140  THE   LEATHER  MANUFACTURE. 

an  "overflow"  or  space  under  tlie  mill  should  be  provided. 
But  a  "  tell  tale  "  should  be  put  on  the  elevators,  plainly  in 
the  sight  of  the  bark  grinder,  so  that  he  can  see  when  there 
is  a  stoppage.  Some  tanners  think  it  a  sufficient  precaution 
to  have  an  opening  in  the  elevator  for  this  observation  ;  but 
a  "  tell  tale  "  should  also  be  placed  on  the  elevators,  and  this 
small  and  inexpensive  lever  should,  in  its  rising  and  falling 
motion,  indicate  its  action  by  a  slight  noise,  so  that  if  the 
eye  is  otherwise  directed  the  ear  of  the  attendant  will  notify 
him  of  the  danger,  which  is  from  breakage  as  well  as  fire. 


OHAPTEE    XVI. 
THE  KOSSING  OF  BAKK. 

THEORIES, OF   THOSE   WHO   ADVOCATE   ROSSING ITS   COST DIFFICULTY  OF 

KOSSING     WITHOUT     TOO      GREAT      LOSS      OF     TANNIN STRENGTH     OP 

LIQUORS   WHICH     MAY     BE     OBTAINED    FROM    ROSSED     AND    UNROSSED 

BARK POSSIBLE   ADVANTAGE   IN    ROSSING   BARK   FOR   EXPORT   IN   THE 

"LEAF." 

To  what  extent,  and  under  what  circumstances,  should  bark 
be  rossed  before  being  ground  for  tanners'  use  ?  If  credit  be 
given  to  the  statements  of  parties  interested  in  the  manu- 
facture and  sale  of  rossing  machines,  tanners  will  be  led  to 
the  conclusion  that  rossing  is  an  absolute  economic  necessity. 
As  the  writer  does  not  agree  with  this  sweeping  conclusion, 
and  yet  believes  that  there  are  circumstances  under  which 
it  is  profitable  to  ross  bark,  the  limitations  which  should 
govern  in  this  matter  will  be  briefly  considered. 

The  theory  on  which  the  rossing  of  bark  is  advocated  may 
be  thus  stated : 

1.  The  outer  ross,  or  dead  bark  of  the  tree,  contains  no 
tannin.  By  the  exposure  of  its  weather-beaten  surface  to  the 
rains  and  winds,  all  but  the  woody >  fibrous  structure  has 
been  destroyed.  To  place  this  porous,  spongy,  woody  fiber 
in  contact,  as  when  ground,  together  with  the  extractive  and 
tannin  matter  of  the  live  portions  of  the  bark,  which  are 
charged  with  tannin,  is  to  absorb  and  dissipate  this  valuable 


142  THE  LEATHER  MANUFACTURE. 

product  to  no  purpose.     Iri  fewer  words,  this  woody  fiber 
will  thus  be  tanned*  and  this  it  is  claimed  is  wasteful. 

2.  The  space  which  this  ross  occupies  in  the  leach  displaces 
so  much  good  bark,  and  to  this  extent  retards  the  leaching 
bj  lessening  the  capacity  of  the  leaches. 

3.  This  dry  ross  is  a  valuable  fuel,  and  can  be  used  to  some 
advantage  in  the  generating  of  steam  or  for  other  purposes. 

Against  these  advantages  should  be  placed  the  cost  of  ross- 
ing,  which  is  quite  inconsiderable,  if  the  advocates  of  ross- 
ing  are  to  be  credited.  Conceding  all  that  is  claimed  for  this 
practice,  it  is  impossible  by  any  machine  yet  invented,  or  even 
by  hand  labor,  to  separate  the  worthless  ross  from  the  live 
bark  so  exactly  as  to  make  the  process  profitable  for  ordinary 
tanners,  who  buy  and  use  their  bark  at  home  in  the  interior 
locations.  Let  any  tanner  who  doubts  this  statement  exam- 
ine carefully  the  ross  coming  from  any  rossing  machine.  Let 
him  place  a  limited  quantity  under  the  influence  of  hot  water, 
and  the  tan  liquor  present  will  be  a  convincing  proof  of  the 
inexpediency  of  the  practice.  Or  let  him  take  a  piece  of 
bark  no  more  than  one  foot  square,  weigh  it  carefully,  and 
then,  by  hand  process,  with  the  aid  of  a  sharp  knife,  let  him 
attempt  to  remove  just  the  colorless  dead  ross,  and  no  more, 
taking  great  care  not  to  touch  the  live  bark.  After  this  is 
done  contrast  the  percentage  of  rejected  ross  with  the  per- 
centage obtained  by  means  of  the  rossing  machines,  and  the 
result  will  show  just  how  much  live  bark  is  taken  for  ross,  to 
burn  up,  by  the  use  of  the  machine.  This  latter  experi- 
ment, conducted  never  so  carefully,  will  also  prove  how  im- 
possible it  is  to  divide  exactly  and  positively  the  dead  and 
worthless  from  the  live  and  valuable  bark.  If  it  cannot  be 
done  by  hand,  even  in  a  small  experimental  way,  how  much 
more  impossible  is  it  to  do  with  a  machine  which  cuts  the 
thin  and  thick  bark  alike — notwithstanding  all  attempts  to 


THE  LEATHER  MANUFACTURE.  143 

adjust  the  knives  and  rollers  to  suit  the  substance  of  the  bark. 
The  testimony  of  tanners  differs  as  to  the  percentage  of 
ross  removed;  most  of  them,  however,  agree  that  even  one- 
iii'th,  or  20  per  cent.,  is  about  the  average  loss.  Some  chemi- 
cal tests  of  the  comparative  strength  of  rossed  and  unrossed 
bark  have  been  made,  and,  naturally  enough,  the  percentage 
of  tannin  in  the  rossed  bark  has  been  found  in  excess  of  that 
in  the  unrosseil.  But  a  recent  and  a  more  satisfactory  ex- 
periment gave  the  following  results:  A  pi^ce  of  average 
hemlock  bark  was  weighed — we  will  suppose  the  weight  to 
have  been  sixteen  pounds.  This  piece  was  first  cut  evenly 
in  two  parts,  and  both  parts  were  afterward  made  to  weigh 
exactly  alike.  The  ross  was  carefully  removed  from  the  one 
piece  by  a  hand  knife  ;  (only  about  one-tenth  of  the  weight 
was  removed,  showing  the  care  with  which  it  was  done.) 
Both  pieces  were  then  separately  ground  fine,  and  leached, 
great  care  being  observed  to  continue  the  equal  condition  all 
through  the  experiment.  The  result  was,  by  the  barkometer 
test,  the  extract  obtained  from  the  unrossed  portion  stood 
higher,  that  is,  indicated  a  greater  degree  of  tannin,  than 
that  portion  which  had  been  rossed.  This  is  an  experiment 
which  any  tanner  can  try  in  a  few  hours,  and  at  small  cost 
of  time  and  labor.  If  the  experiment  is  tried  accurately,  it 
will  be  found  that,  without  considering  the  cost  of  rossing, 
there  is  a  positive  economic  loss  in  the  process.  In  no  in- 
stance, however,  has  the  strength  differed  equal  to  the  loss 
of  the  ross,  which  we  assume  to  be  20  to  25  per  cent.  The 
experiments  show  that  hemlock  bark  that  is  rossed  will  give 
8.66  per  cent.,  while  the  same  bark  not  rossed  will  give  7.13 
per  cent.  The  experiment  was  made  by  a  celebrated  Boston 
chemist  in  the  interest  of  the  patentee  of  a  bark  rosser,  and 
may  at  least  be  taken  as  the  most  favorable  result  which  can 
be  produced. 


144  THE  LEATHEli  MANUFACTURE. 

If  this  is  the  result  of  the  comparative  strength  of  bark, 
rossed  and  unrossed,  we  are  left  to  consider  on  the  one  hand 
the  cost  of  rossing,  and  on  the  other  the  value  of  the  dry 
material.  The  cost  of  rossing,  independent  of  grinding,  may 
fairly  be  placed  at  fifty  cents  per  cord,  and  the  dry  ross  ob- 
tained equal  to  400  pounds.  Is  400  pounds  of  ross  worth 
fifty  cents?  Of  course  this  would  depend  upon  the  value  of 
fuel  in  the  locality.  To  the  ordinary  tanner  the  dry  ross  is 
worthless,  and  woiid  hardly  pay  for  its  remova!,  since  the 
wet  spent  tan  furnishes  far  more  steam  power  than  suffices  for 
driving  the  whole  machinery  of  the  tannery,  and  dry  ross  is  a 
poor  substitute  for  wood  anywhere  else  than  under  a  furnace. 

But  there  are  circumstances  which  would  justify  rossing 
as,  for  instance,  if  bark  had  to  be  transported  long  distances, 
where  the  cost  of  transportation  was  a  considerable  item  of 
the  value  ;  or,  if  the  bark  had  to  be  "  baled,"  and  the  freight 
was  based  both  upon  bulk  and  weight,  then  would  it  be  es- 
pecially necessary  to  ross.  It  has  often  occured  to  the  writer 
that  both  the  English  and  German  tanners  would  find  it  prof- 
itable to  buy  our  oak  and  hemlock  bark  and  closely  ross  and 
bale  for  shipment  to  their  market.  Bossed  bark  in  the  "leaf" 
will  occupy  one-quarter  less  space  than  when  "in  the  rough," 
and  with  care  may  be  so  compactly  placed  in  a  bale  as  to 
make  solid  stowage — so  solid,  indeed,  that  no  ordinary  lev- 
erage can  compress  it.  "When  thus  baled,  and  bound  with 
wire,  there  can  be  no  doubt  that  bark  could  be  sent  to  Europe 
from  many  of  our  Southern  ports  to  advantage.  The  cost 
would  be  as  follows : 

Original  cost  of  oak  bark,  per  ton $10  00 

Cost  of  freight  to  seaboard 4  00 

Cost  of  baling  and  rossing 2  00 

Freight  to  Liverpool 5  00 

Total..  .  $2fOO 


THE   LEATHER  MANUFACTURE.  145 

Southern  oak  bark,  thus  rossed  and  baled,  would  give  Eu- 
ropean tanners  better  and  cheaper  tanning  material  than 
they  at  present  employ  from  any  barks  in  the  "leaf"  or 
"chip"  which  they  now  use.  Whether  " extract "  from  this 
bark  could  not  more  economically  be  sent  abroad,  is  quite  a 
different  question,  which  the  writer  will  not  here  enter  upon. 


CHAPTEE    XVII. 
UTILIZATION  OF  TANNERY  REFUSE. 

BURNING     THE    WET    TAN — GLUE   STOCK IMPORTANCE    OF    KEEPING    THE 

PIECES  PURE  AND  SWEET PRESERVING,  CLEANSING    AND  DRYING  THEM 

USES  FOR  CATTLE  HAIR THAT  WHICH  COMES  FROM  SWEAT  OR  LIMED 

STOCK — WASHING,  DRYING  AND  PACKING FERTILIZING   LIQUIDS   FROM 

THE  LIMES  AND  SOAKS. 

Previous  to  the  year  1852  it  was  customary  in  all  the  tan- 
neries of  New  England  to  dry,  or  partially  dry,  in  the  open 
air,  all  the  spent  tan  from  the  yard  and  leaches,  and  store 
during  the  summer  months  for  winter  use,  not  only  for  heat- 
ing the  liquors,  but,  in  exceptional  cases,  to  generate  steam 
to  furnish  the  power  for  the  ordinary  work  of  the  tannery. 
Even  up  to  this  day  the  practice  is  regarded  as  most  eco- 
nomical by  the  upper  leather  tanners,  and  such  others  as  do 
much  finishing.  None  of  the  patented,  or  unpatented,  meth- 
ods of  burning  wet  tan  can  secure  as  good  a  result  with  wet 
as  they  can  with  dry  tan.  Experience  has  shown  that  from 
one-third  to  one-half  the  effective  heat-producing  power  is 
neutralized  in  driving  off  the  water.  In  other  words,  there 
is  no  method  of  burning  wet  tan  that  does  not  first  evaporate 
the  water.  Therefore,  when  there  is  an  inadequate  supply 
of  tan,  and  it  is  convenient  to  dry  it,  it  is  always  better  to  do 
so.  But  in  the  case  of  our  sole  leather  tanners,  they  have  a 


THE  LEATHER  MANUFACTURE.  147 

surplus  of  wet  tan,  and  to  waste  it  by  burning  a  profuse 
quantity  is  to  save  the  expense  of  otherwise  disposing  of  it. 

In  the  year  1852  Mr.  Joseph  B.  Hoyt  conceived  the  idea 
of  burning  wet  spent  tan  in  a  detached  brick  furnace,  and 
did  for  the  first  time  in  America  succeed  in  obtaining  the 
power  to  drive  his  machinery  by  this  agency,  unaided  and 
alone.  This  was  done  at  his  tannery  at  Woodstock,  Ulster 
County,  N.  Y.,  and  the  event  has  been  made  memorable  by 
the  great  success  which  has  attended  the  practice  ever  since. 
This  improvement  revolutionized  the  construction  of  our  tan- 
neries. It  rendered  water  power  of  little  or  no  value.  It 
caused  tanneries  to  be  located  upon  open  flats,  where  access 
could  be  had  from  all  parts  to  the  buildings,  and  took  them 
from  the  banks  of  the  streams,  where  floods  and  overflows 
did  yearly  great  damage  ;  it  rendered  unnecessary  the  use  of 
wood  or  coal  for  the  heating  of  liquors,  or  the  warming  of  the 
lofts,  and,  by  the  unlimited  and  inexpensive  use  of  this  newly- 
acquired  agent,  labor  saving  machinery  was  introduced  every- 
where. 

The  controversy  about  the  priority  of  the  invention  or  use 
of  wet  spent  tan,  commenced  in  1869,  occupied  the  attention 
of  one  of  our  courts  for  six  years  or  more,  and  the  decision 
finally  reached  was  that  Mr.  Hoyt  and  his  agent,  Mr.  Crock- 
ett, did  introduce  these  wet  tan  burning  ovens  as  early  as 
1852,  and  by  their  use  a  result  was  obtained  equal  to  any 
which  has  been  secured  by  any  improvement  since  made. 

Notwithstanding  the  publicity  which  has  been  given  to  the 
construction  of  furnaces  for  the  utilization  of  this  refuse, 
there  has  been  no  one  specific  plan  that  has  received  general 
commendation.  So  many  of  these  furnaces  have  been  adapt- 
ed to  the  condition  of  the  structures  already  in  existence, 
that,  with  the  exception  of  those  tanneries  built  within  the 
past  ten  years,  there  has  been  no  consistent  and  harmonious 


148  THE  LEATHER  MANUFACTURE. 

plan  of  construction.  "With  a  fuel  so  abundant,  and  withal 
so  worthless,  economy  in  the  consumption  was  best  studied 
by  practicing  the  most  wasteful  methods,  and  hence  it  has 
been  customary  for  tanners  to  economize  in  the  construction 
of  their  boilers  at  the  expense  of  their  fuel.  "Log"  or  "cyl- 
inder "  boilers  being  much  cheaper  and  more  durable,  they 
have  in  many  instances  been  introduced  instead  of  "flue"  or 
"  tubular  "  boilers,  not  because  they  were  more  economical, 
but  in  truth  because  they  were  more  wasteful  of  fuel.  Sev- 
eral of  our  tanners  have  been  compelled  to  construct  brick 
furnaces  outside  and  independent  of  their  ordinary  boilers, 
in  order  to  "  get  rid  of "  their  surplus  spent  tan.  As  time 
goes  on,  however,  and  as  we  come  more  generally  into  the 
nse  of  mechanical  power,  there  will  be  less  solicitude  to  get 
rid  of  this  refuse  without  bringing  it  within  our  service.  No 
town  or  city  is  without  its  mechanical  appliances,  and  if  the 
power  or  heat  is  not  required  for  the  tannery,  it  can  be  ap- 
plied to  some  other  purpose.  It  may  be  sent  off  to  the  dis- 
tance of  several  hundred  and  even  several  thousand  feet  to 
drive  an  elevator  or  an  engine,  or  warm  some  dwelling  or 
manufactory.  There  is  no  reason  why  all  the  power  should 
not  be  utilized,  and  hence  the  writer  would  strongly  commend 
the  use  of  tubular  or  at  least  flue  boilers  in  all  cases. 

As  the  subject  of  burning  wet  spent  tan,  both  in  its  eco- 
nomic and  scientific  relations  to  the  tanner,  is  considered  in 
a  subsequent  portion  of  this  book,  the  subject  may  be  dis- 
missed for  the  present  with  the  statement,  which  seems  nec- 
essary in  this  connection,  that  the  spent  tan  can  be  so  utilized 
as  to  give  all  the  power  required  by  the  tanner  in  softening 
his  dry  hides,  in  grinding  his  bark,  in  rolling  and  finishing 
his  leather,  in  warming  his  building,  in  heating  his  liquors, 
and  in  doing  such  other  service  as  may  be  done  by  mechani- 
ical  power. 

i 


THE   LEATHER  MANUFACTURE.  149 

The  glue  stack,  of  which  every  tanner  has  more  or  less,  is 
valuable  almost  in  proportion  to  the  care  bestowed  upon  its 
preservation,  and  this  is  true  without  considering  the  higher 
grades  of  gelatine  which  are  made  from  calves'  pates  and 
feet,  and  the  sinews  from  neats  animals.  These  are,  or 
should  be,  preserved  by  the  slaughterer,  and  handed  over 
to  the  manufacturer  of  gelatines  for  human  food.  In  the 
preservation  of  tanners'  hide  offal,  as  it  is  known  to  come 
from  ordinary  dry  and  green  hides  and  skius,  it  is  of  the  first 
importance  that  the  "glue"  or  "size"  pieces  should  be 
sweet  and  pure  from  all  "taint"  or  "smell."  The  paper 
makers  use  animal  "size"  very  extensively,  and  such  as  they 
use  must  be  absolutely  free  from  all  bad  odors,  otherwise 
the  paper  is  rendered  worthless.  With  all  the  care  which 
the  paper  makers  exercise  they  do  occasionally  use  "tainted" 
size,  and  the  odor  will  cling  to  the  paper  forever,  greatly  less- 
ening if  not  entirely  destroying  its  value.  Next  in  import- 
ance to  paper  size  comes  the  fine  glues  which  are  used  in 
book  and  furniture  work.  In  these,  too,  it  is  of  great  im- 
portance that  there  should  be  perfect  purity  and  freedom 
from  all  smell.  It  is  only  for  the  most- common  use,  such  as 
preparing  petroleum  barrels,  sizing  woodwork,  etc.,  that  glue 
that  has  been  in  the  least  tainted  can  be  used ;  therefore  it 
is  that  the  value  of  this  stock  depends  almost  entirely  upon 
the  care  taken  in  its  preservation  from  all  bad  odors. 

When  the  hides  or  skins  are  either  fresh  from  the  animal 
or  have  been  properly  cured  with  salt  there  is  no  difficulty 
in  avoiding  all  decomposition — indeed,  nothing  but  absolute 
carelessness  can  bring  harm  to  the  "glue  pieces."  But  if 
the  pelts  have  been  dried,  and  require  to  be  softened  before 
being  limed  or  sweat,  then  it  is  that  care  and  close  and 
prompt  attention  should  be  given  to  the  preservation  of  this 
valuable  offal.  Whether  from  green  or  dry  stock,  the  trim- 


150  THE  LEATHER  MANUFACTURE. 

mings  should  be  thrown  into  a  weak  lime  as  soon  as  they  leave 
the  beam,  and  should  be  retained  in  this  lime  until  the  hair 
will  almost  drop  off;  when  in  this  condition  they  should  be 
thrown  into  a  revolving  wheel,  or  may  be  put  in  the  hide 
mill,  and  worked  until  all  the  hair  has  been  separated  from 
the  pieces.  If  a  bountiful  supply  of  water  has  been  allowed 
to  run  on  while  the  wheel  or  mill  was  in  operation,  all  the 
hair  will  have  been  worked  off  and  separated  from  the 
pieces,  which  will  then  have  parted  with  so  much  of  their 
lime  as  to  make  them,  when  dry,  flinty  and  hard ;  to  avoid 
this  they  should  be  thrown  back  into  the  lime  for  a  few  days, 
and  again  "  raised."  Before  they  are  taken  out  to  dry  they 
should  be  thoroughly  washed.  The  drying  should  be  in  the 
open  air,  and  if  on  a  flat  board  surface  then  the  pieces  should 
be  frequently  turned.  Care  should  be  taken  to  wash  off  all 
the  loose  lime,  so  that  the  pieces  may  present  an  attractive, 
uniform  white  clean  surface.  When  they  are  fully  dried  they 
should  be  pr3ssed  into  uniform  bales.  Under  no  circum- 
stances should  any  tainted  or  damaged  piece  be  allowed  to 
go  in  the  bale.  Paper  makers  will  use  such  hide  offal  for 
sizing,  and  pay  three  or  four  cents  per  pound  more  for  it 
than  glue  makers  can  afford  to  pay.  Calfskin  shanks  and 
pates  are  worth  more  for  this  purpose  than  hide  cuttings, 
and  should  always  be  kept  separate. 

Until  within  a  few  years  cattle  and  calves'  hair  have  only 
been  used  for  plastering  purposes,  and  for  this  the  harshness 
produced  by  the  liming  process  rather  added  to  than  de- 
tracted from  its  value  ;  but  more  recently  this  hair,  particu- 
larly the  calves'  hair,  has  been  used  for  cloth,  carpets  and 
felting,  and  for  these  purposes  it  is  required  to  be  soft,  which 
necessitates  freedom  from  lime.  Probably  it  will  be  ulti- 
mately demonstrated  that  the  hair  from  hides  that  are  uii- 
haired  by  sweating,  so  far  as  the  length  (as  in  winter  and 


THE  LEATHER  MANUFACTURE.  151 

sp.ing  hides)  will  serve,  is  far  superior  to  limed  hair  for  this 
very  reason.  Millions  of  pounds  of  this  valuable  product, 
that  should  have  at  least  gone  on  the  "fertilizing  heap,"  if 
its  length  had  been  too  short  for  cloth  or  felting,  have  been 
washed  down  the  streams. 

It  is  important  to  select  the  white  hair  from  all  other  colors, 
as  it  is  worth  nearly  or  quite  double  the  price  of  the  general 
stock.  This  selection  is  not  attended  with  much  inconven- 
ience if  done  while  the  beam  work  is  in  progress.  If  the  hide 
or  skin  is  white,  or  mainly  so,  it  should  be  thrown  to  the  beam 
hand  whose  duty  it  is  to  unhair  this  color ;  when  he  has  re- 
moved all  the  white  hair  he  passes  the  skin  or  hide  to  his 
companion,  and  so  in  turn  they  pass  to  him  all  their  pelts 
that  have  any  considerable  amount  of  white  hair.  In  this 
way  a  single  beam  hand  accumulates  at  his  beam  all  the 
white  hair,  and  of  course  it  can  be  easily  dried  and  kept 
separate. 

The  cleansing  of  the  hair  from  the  lime  is  attended  with 
little  or  no  expense.  Throughout  Europe  it  is  washed  by 
hand,  large  splint  baskets  being  used  ;  filling  a  basket  about 
half  full,  an  attendant,  standing  on  the  bank  of  a  stream, 
plunges  it  in  and  lifts  it  up  until  the  currents  of  water  passing 
through  carry  off  most  of  the  lime.  But  in  this  country  a 
vat  with  a  false  bottom  is  used  to  better  effect.  The  vat  is 
placed  so  as  to  command  a  bountiful  supply  of  water,  and  it 
has  a  false  bottom  bored  fall  of  small  holes — large  enough  to 
allow  the  lime  water  and  small  particles  of  lime  to  pass 
through,  while  retaining  the  hair.  While  the  hair  is  covered 
with  water,  and  is  being  plunged,  the  openings  iu  the  bottom 
must  be  closed  ;  when  the  agitation  of  the  contents  is  com- 
pleted, the  plugs  may  be  drawn  from  the  bottom,  and,  prac- 
tically, the  particles  of  lime  having  gone  down  below  the 
false  bottom,  the  hair  will  mat  together,  settle  down  and  rest 


152  THE  LEATHEE  MANUFACTURE. 

on  the  false  bottom ;  very  little  or  none  of  the  serviceable 
long  hair  will  have  passed  out.  This  process  of  fi'ling,  plung- 
ing and  draining  off  may  be  repeated  a  dozen  times  during 
xbe  day,  and  the  hair  will  be  fairly  cleansed.  If  it  is  desira- 
b  3  to  cleanse  the  fiber  of  the  hair  from  the  effects  of  the 
lime,  warm  water  run  on  the  last  time,  and  allowed  to  remain 
for  a  short  period,  will  greatly  aid  this  result.  This  latter 
process  will  leave  the  hair  much  softer  than  if  cleansed  only 
with  cold  water.  When  it  shall  be  established,  as  now  seems 
pr  ;table,  that  all  calves'  and  cattle  hair  can  be  utilized  in 
making  coarse  blankets,  cheap  carpets  and  felting,  other 
methods  for  neutralizing  the  lime  will  come  into  vogue. 

Never  until  within  the  past  few  years  has  the  hair  from 
"hides  unhaired  by  sweating  been  saved.  Whether  the  hair 
was  long  or  short  it  has  all  been  allowed  to  pass  down  the 
sstream  from  the  mills,  or  if  saved  from  the  beam  it  has,  in 
•exceptional  cases,  been  used  as  a  fertilizer.  It  is  now  de- 
monstrated that  hair  from  such  stock  is  more  valuable  for 
all  the  purposes  above  referred  to  than  when  limed,  and  when 
the  long  haired  hides  are  milled  by  themselves  the  hair  will 
always  pay  the  labor  of  saving.  For  felting,  all  hair  from 
hides  unhaired  by  sweating,  both  long  and  short,  is  servicea- 
ble, and  should  never  be  wasted. 

The  principal  expense  in  saving  hair  heretofore  has  been 
in  the  drying.  This  is  obviated  by  a  very  simple  contrivance, 
as  follows :  Make  a  plank  box  eight  or  ten  feet  long,  four  to 
six  feet  wide,  and  say  two  feet  high ;  under  a  false  bottom 
•run  a  net  work  of  steam  pipe;  place  the  pipe  midway  be- 
-tween  the  bottom  and  the  latticed  false  "Bottom,  so  far  dis- 
tant from  each  that  a  broom  may  freely  pass  to  clear  out  the 
accumulating  lime  dust — and  when  thus  prepared  turn  on  the 
exhaust  steam  from  your  nearest  engine,  allowing  the  steam 
to  condense  through  this  piping  and  under  this  false  bottom. 


THE   LEATHEK   MANUFACTUKE.  153 

Hair  may  be  thrown  into  this  box  to  the  depth  of  one  foot, 
and  will  only  require  occasional  stirring  for  an  hour  to  make 
it  thoroughly  dry.  In  this  way  the  hair  may  be  dried  ready 
for  packing,  while  occupying  but  a  small  room  space  and  at 
an  inconsiderable  expenditure  of  labor. 

Hair  may  be  packed  for  transportation  in  bales,  pressed  as 
hay  is  (indeed,  hay  packing  machines  may  be  used  for  the 
purpose),  or  in  sacks  made  of  burlaps,  as  wool  is  usually 
packed.  If  pressed  in  bales,  refuse  boards  should  be  placed 
on  the  bottom  and  top,  and  the  whole  bound  with  wire,  pre- 
cisely as  hay  is  now  brought  to  market.  When  thus  packed, 
fully  500  pounds  can  be  placed  in  a  bale  four  feet  square. 

The  water  from  the  soaks,  as  well  as  the  exhausted  lime 
and  bate  liquor  (including  the  wash  from  the  hide  mills  and 
beam  house),  should  all  be  collected  together  in  a  capacious 
reservoir  situated  below  the  level  of  the  tannery  foundation, 
so  that  all  these  valuable  liquid  manures  may  be  brought 
together  without  the  labor  of  elevating.  This  reservoir  may 
be  at  any  distance  from  the  beam  house ;  indeed,  it  is  far 
better  to  be  removed  a  few  hundred  feet  than  close  by.  It 
should  be  capacious  enough  to  hold  not  only  the  liquid 
refuse,  but  also  all  solids  which  come  from  the  sweepings 
and  scrapings  of  the  beam  house  floor  and  drying  lofts. 
So  valuable  are  these  washings  that  the  writer  has  known  a 
small  tanner  to  fertilize  a  hundred  acres  by  the  refuse  of  a 
five  thousand  hide  tannery.  Old  spent  tan,  fine  chips  or 
shavings,  and  even  earth,  may  be  carted  and  thrown  into  this 
fertilizer  reservoir,  and  allowed  to  absorb  the  ammonia,  and 
then  removed  to  the  land,  with  great  profit. 

A  tanner  with  poor  land  about  him,  who  allows  his  refuse 
liquids  to  run  into  the  stream,  is  culpably  thoughtless ;  and 
yet  such  instances  are  numerous,  notably  so  in  the  St-ite  of 
Maryland,  where  the  writer  has  seen  hundreds  of  loads  of 


154  THE  LEATHER  MANUFACTURE. 

the  residuum  of  spent  limes  and  bates  piled  up  around  the 
tannery.  As  the  law  forbade  the  tanner  from  throwing  these 
objectionable  substances  into  the  stream,  and  as  he  owned  no 
land,  and  was  surrounded  with  shiftless  fanners,  large  piles 
of  the  most  valuable  fertilizers  remained  to  obstruct  his  way. 
The  single  tannery  to  which  allusion  is  made  could  fertilize, 
if  all  liquid  and  solid  matter  of  the  beam  house  was  distrib- 
uted, more  than  400  acres  ol  land. 


CHAPTEK    XVIII. 
TANNING     MATEEIALS. 

DIFFERENT  KINDS  OP  HEMLOCK  BARK INFLUENCE  OF  SOIL  AND  CLIMATE 

ON  THE  QUALITY HEAVY  AND  LIGHT  BARK VARIETIES  OF  OAK  BARK 

— THE  "SECOND  GROWTH"  BETTER  THAN  THE  FIRST — GAMBIER — ITS 

GROWTH  AND  PREPARATION  FOR  MARKET ITS  COST  COMPARED  WITH 

THAT  OF  BARK VALONIA,  DIVE  DIVI,  MYRABOLAMS "  SWEET  FERN/'' 

ETC. 

On  the  American  Continent,  bark  is  the  principal  material 
for  sole  leather  tanning,  and  although  many  attempts  have 
been  made  to  supersede  its  use,  they  have  for  the  most  part 
failed.  The  reasons  for  these  failures  are  not  very  difficult 
to  find,  and  should  convince  that  large  class  of  experimenters 
who  rely  upon  "  sweet  fern,"  "  salt,"  "  alum,"  "  terra  japonica" 
and  the  like  substitutes  that  the  day  is  far  distant  when, 
in  this  country,  any  other  substance  than  bark  tannin  will  be 
successfully  used  for  manufacturing  leather. 

The  tannin  from  hemlock  bark,  probably,  tans  eight-tenths 
of  all  the  leather  made  in  America,  and  notwithstanding  the 
opinion  entertained  in  England — and  in  this  country  too,  by 
a  few — that  hemlock  is  inferior  to  oak,  as  a  tanning  material, 
the  writer  believes  that,  so  far  as  the  question  is  susceptible 
of  demonstration,  this  opinion  is  erroneous. 

But  to  pass,  for  the  present,  from  the  consideration  of  the 
comparative  merits  of  the  manufactured  article,  and  consider 
only  the  comparative  cost  and  value  of  the  bark  as  a  tanning 


156  THE   LEATHER   MANUFACTURE. 

material,  it  should  first  be  stated  that  there  are  two  kinds 
of  hemlock — white  and  red — and  although  there  is  a  great 
difference  in  the  timber  of  the  two  kinds,  there  is  not  much 
distinction  in  the  tanning  qualities  of  the  bark.  Some  tanners 
think  there  is  a  dissimilarity  in  strength,  and  also  in  color, 
but  the  conceded  difference  between  hemlock  barks  may  be 
attributed  to  other  causes  than  this  difference  of  "species." 

Soil  and  climate  we  know  influence  the  tanning  qualities 
of  all  barks,  and  none  more  than  the  hemlock.  All  tanners 
know  that  hemlock  bark  from  low,  marshy  ground,  or  the 
swales  of  the  hills  and  mountains,  is  much  thicker  than  from 
the  high  lands  and  mountains,  and  further,  that  a  southern 
exposure  produces  more  thrifty  trees,  and  consequently 
thicker  bark.  The  wash  of  the  mountains,  of  course,  feeds  and 
enriches  the  valleys,  giving  richer  soil  and  damper  earth,  both 
of  which  are  indispensible  to  rank  vegetable  growth.  It  may 
not  be  generally  known  that  all  barks,  like  all  woods,  are 
made  up  of  distinct  layers  or  deposits,  one  layer  being  formed 
each  year.  This  formation  takes  its  character  from  the  soil 
and  the  season  ;  if  in  rich  soil  and  damp,  wet  surroundings, 
the  layers  will  be  thick,  and  "  fat"  with  tannin,  but  if  other- 
wise, the  layers  will  be  thin,  and  the  tannin  "lean."  So  uni- 
form and  unerring  are  the  laws  governing  these  deposits,  that 
naturalists  claim  they  can  not  only  tell  the  exact  age  of  the 
tree,  but  they  can  determine  with  considerable  accuracy  the 
nature  of  the  seasons  through  which  the  life  has  progressed. 
Assuming  then  that  tannin  is  deposited  just  in  proportion  as 
the  growth  of  the  bark  or  tree  is  rank  and  healthy,  we  can 
easily  see  how  it  happens  that  in  some  sections  of  the  coun- 
try a  cord  of  hemlock  bark  will  weigh  1,600  to  1,800  pounds, 
and  tan  but  140  to  150  pounds  of  leather,  while  in  other 
sections  a  cord  will  weigh  2,200  to  2,300  pounds,  and  tan  200 
pounds  of  leather.  These  may  be  taken  as  extremes  of  qual- 


THE  LEATHER  MANUFACTURE .  157 

ity,  but  to  find  these  extremes  one  need  not  go  out  of  the 
same  neighborhood.  The  swamp  bark  represents  the  ono 
extreme,  and  the  high  mountain  bark,  particularly  if  having 
a  northern  exposure,  the  other  extreme  ;  and  yet,  while  this 
difference  is  known  to  all  well-informed  tanners,  they  con- 
tinue to  pay  the  same  price  for  each  kind,  and  wonder  why  one 
cannot  tan  as  cheap  as  another.  But  there  is  a  further  con- 
sideration which  weighs  against  the  light  bark,  and  it  is  this  : 
the  small,  stunted  growth  bark  will  curl,  forming  "  gun  bar- 
rels," while  that  from  the  heavy  swamp  timber  will  lie  flat. 
This  fact  goes,  to  some  extent,  to  make  up  the  great  differ- 
ence between  the  cord  of  1,600  pounds  and  that  of  2,300 
pounds,  but  the  assumption  of  inferiority  is  outside  and  in- 
dependent of  this  disparity  of  measure ;  if  the  premises  are 
right,  2,000  pounds  of  heavy  hemlock  bark  will  tan  more  than 
2,000  pounds  of  light  hemlock.  Practically  the  difference 
cannot  be  very  great,  but  so  long  as  tanners  continue  the 
unjust  practice  of  buying  bark  by  the  cord,  instead  of  the  ton, 
they  will  do  themselves  this  wrong.  The  writer  knows  of  a 
location  where,  for  many  years,  the  competition  for  bark  has 
been  very  strong  ;  but  one  tanner,  appreciating  the  difference 
above  referred  to,  has  always  selected  and  purchased  the  lots 
of  heavy  bark,  paying  from  one  to  four  shillings  per  cord 
more  than  his  neighbors,  by  which  means  he  has,  probably, 
paid  less  for'  the  actual  tanning  material  than  any  of  his  com- 
petitors. Why  should  one  bark  peeler  be  required  to  rank 
and  draw  2,300  pounds  from  six  to  ten  miles  for  the  same 
price  that  another  gets  for  1,600  pounds  ?  The  injustice 
both  to  the  tanner  and  bark  peeler  must  be  very  apparent. 
The  light  hemlock  bark  is  supposed  to  impart  less  coloring 
matter  than  the  heavy.  This  is  possibly  true ;  indeed,  it  is 
so  in  tha  judgment  of  some  of  our  best-informed  Eastern 
tanners.  Acting  on  this  supposition,  the  fair  leather  tanners 


158  THE  LEATHER  MANUFACTURE. 

of  Connecticut  and  Massachusetts  continue  to  use  the  light 
hemlock  obtained  from  the  upper  counties  of  Massachusetts 
and  Vermont,  supposing  that  the  want  of  coloring  matter 
will  compensate  them  for  the  deficiency  of  strength.  The 
beautiful  lemon  color  produced  by  the  Connecticut  and  Mas- 
sachusetts sheepskin  tanners  may  be  the  result  of  ihe-tveak 
but  pure  liquors  which  they  use,  but  if  they  subjected  their 
bark  to  the  same  heating  and  leaching  process  as  that  of  our 
sole  leather  tanners,  possibly  the  difference  would  not  be  as 
great  as  is  now  imagined.  However  this  may  be,  .the  sup- 
posed difference  in  the  coloring  matter  of  hemlock  bark  is 
keeping  several  large  fair  leather  tanners  in  Connecticut  from 
availing  themselves  of  the  cheaper  hemlock  of  Pennsylvania 
and  New  York. 

To  verify  the  theory  here  presented  in  regard  to  the  quality 
of  bark,  let  the  reflecting  tanner  pass  over  in  his  mind,  as  he 
readily  may,  the  whole  tanning  region  of  the  country,  com- 
mencing with  Maine,  on  the  East.  There  we  find  a  cold 
climate,  and  for  the  most  part  a  poor  soil.  The  valleys  of 
the  Aroostook,  the  low  lands  surrounding  Moosehead  and 
other  lakes,  may  be  exceptions ;  but  generally  these  rich  lands 
are  covered  with  pine,  and  have  only  occasional  patches  of 
hemlock.  The  hemlock  bark  from  that  State  is  thin,  and  will 
not  weigh,  as  bark  is  ordinarily  measured  at  our  tanneries, 
over  1,800  pounds  to  the  cord.  The  same  general  character 
holds  true  of  the  bark  of  all  the  New  England  States.  In 
the  lower  counties  of  the  State  of  New  York  we  have  a 
warmer  climate  and  a  more  diversified  soil ;  where  the  soil  is 
favorable  we  have  thick  bark,  but  the  hills  and  mountains  give 
us  much  thin  bark. .  This  is  true  of  Northern  and  Eastern 
Pennsylvania  also ;  but  as  we  proceed  West  and  South  in 
New  York  and  Pennsylvania,  the  country  is  more  open  and 
level,  the  soil  richer,  and  we  have  a  more  uniform  and  much 


THE   LEATHER   MANUFACTURE.  159 

thicker  bark.  Take  those  counties  where  wheat  grows  nat- 
urally, not  merely  on  the  river  bottoms,  but  on  the  slopes  of 
the  highest  hills  and  mountains— where  you  can  see  no  "  bar- 
ren wastes,"  as  in  Eastern  and  Central  New  York — and  you 
are  sure  to  find  thrifty  trees,  with  long  bodies  and  thick  bark 
—bark  that  will  weigh  2,200  to  2,300  pounds  to  the  cord. 

The  effect  of  soil  and  climate  on  the  growth  and  strength 
is  still  more  apparent  in  oak  bark.  The  bark  from  this  tree 
is  comparatively  worthless  in  a  cold  latitude,  while  in  Lower 
Pennsylvania,  Maryland  and  Yirginia,  it  is  strong.  There  it 
grows  on  the  bottom  lands ;  this,  with  the  warm  climate, 
gives  the  rank  growth.  But  in  New  York  the  oak  grows  only 
on  the  hills  and  ridges,  being  crowded  out  from  the  swales 
by  the  hemlock,  birch,  beech,  and  maple,  so  that  we  cannot 
say  what  it  might  do  under  more  favorable  circumstances. 

It  was  suggested  by  the  late  Col.  Pratt,  and  has  been  re- 
remarked  by  other  observers,  that  sea  air  has  something  to 
do  with  the  strength  of  bark.  This  observation,  confined  to 
oak,  certainly  seems  to  be  verified  by  the  known  facts,  for  the 
oak  of  Ohio,  Michigan  and  the  Western  States  generally  is 
very  weak — scarcely  strong  enough,  as  now  used,  to  furnish 
liquors  of  sufficient  strength  to  preserve  the  hide  from  putre- 
faction. But  may  it  not  be  that  the  oak  of  those  States  is  of 
a  different  kind  from  ours  ?  The  writer  has  not  seen  rock 
oak  there,  but  has  seen  white  oak  and  red  oak  of  im- 
mense size  and  growth.  This  white  oak  bark  is  a  poor  tan- 
ning material,  and  the  red  oak  but  little  better — scarcely 
yielding  enough  tannin  to  pay  for  peeling.  May  it  not  be 
that  the  influence  of  sea  air  makes  the  difference  between 
their  oak  and  ours  ? 

How  many  pounds  of  leather  will  a  cord  of  hemlock  bark 
make  ?  This  question,  a  thousand  times  asked,  has  never 
been  answered,  and  never  can  be,  until  a  more  certain  rule  of 


160  THE  LEATHER  MANUFACTURE. 

measurement  is  determined  upon.  As  already  hinted,  if  in 
a  new  location,  where  strong  competition  does  not  compel 
the  tanner  to  take  90  to  100  feet  for  a  cord,  but  where  he  can 
get  128  solid  square  feet,  and  that,  too,  of  good,  heavy  bark 
(and  the  heavy  bark  is  always  peeled  first,  for  obvious 
reasons),  then  200  pounds  of  leather  can  be  made  from  one 
cord  of  bark ;  but  if  these  conditions  are  otherwise,  then  from 
130  to  150  pounds — and  it  is  safe  to  say  that  throughout  the 
old  tanning  districts  of  New  York  State  160  pounds  is  a  full 
average. 

Little  need  be  said  of  oak  bark,  for  its  merits  are  appre- 
ciated the  world  over.  In  this  country  we  have  the  following 
kinds:  Rock  Oak,  (called  by  some  "chestnut  oak;")  'Yellow 
Oak  (called  sometimes  "  black  oak,"  from  the  dark,  black  ex- 
terior, but  by  tanners  called  "yellow,"  from  the  fact  that  a 
very  yellow  color  is  produced  by  its  bark;)  Led  Oak  and 
White  Oak.  The  first  two  are  considered  the  most  desirable. 
Their  strength  is  about  equal.  The  coloring  matter,  how- 
ever, of  the  yellow  oak  is  so  objectionable  for  sole  leather 
that,  unless  used  with  red  oak  or  hemlock,  its  value  is  very 
much  impaired,  but  it  is  valuable  for  dyeing  purposes,  and  is 
exported  from  Philadelphia  and  Baltimore  in  large  quantities, 
under  the  name  of  "  quercitron  bark."  This  bark  (although 
of  rather  inferior  quality)  is  found  in  large  quantities  in  the 
State  of  New  Jersey. 

Wliite,  Oak  makes  a  beautiful  leather,  but  the  tannin  it  con- 
tains is  so  small  in  amount  as  to  render  it  almost  worthless — 
certainly  not  more  than  half  as  valuable  as  the  better  de- 
scriptions of  oak.  The  coloring  matter,  too,  although  very 
good  of  i  itself,  is  too  weak  to  be  of  much  value  as  a  dye. 

Red  Oak  is  a  heavy,  hard  bark  to  manage — difficult  to 
grind,  and  heavy  to  handle — and  when  leached  or  used  as  a 
"duster,"  produces  a  "mean"  red  color,  without  the  "fresh 


THE  LEATHER  MANUFACTURE.  161 

hue"  of  the  hemlock,  or  the  "true  bloom"  of  the  oak,  and 
would  seldom  be  used  for  its  own  sake — but  the  wood  is  val- 
uable for  staves,  and  hence  the  bark  is  peeled,  and  finds  its 
way  to  the  tanner,  and,  to  his  detriment,  he  is  often  induced 
to  use  it. 

The  original  oak — that  is,  the  first  growth,  even  of  the 
best  descriptions,  is  quite  inferior  as  a  tanning  material; 
but  the  second  growth — the  young  trees,  say  from  fifteen  to 
twenty-five  years  old,  particularly  of  the  rock  oak — is  very 
valuable,  and,  when  properly  blended  with  hemlock,  makes  a 
leather  which,  for  color  and  wear,  will  compare  favorably 
with  the  best  tannages  of  the  world. 

The  effect  of  age  upon  the  oak  tree  is  to  cause  it  to  throw 
off  a  dead  ross,  which  loses  its  tanning  qualities ;  hence,  until 
within  a  few  years,  it  was  customary  with  all  our  oak  tanners 
to  ross  their  bark — throwing  away  as  worthless  fully  one- 
third  the  substance  of  the  bark ;  but,  after  using  up  the  old 
first  growth,  and  coming  down,  as  we  now  have,  to  the 
second  growth,  which  has  much  less  of  this  dead  ross,  the 
practice  has  gone  into  disuse. 

Oak  trees  reproduce  themselves  in  about  twenty  to  thirty 
ye  Mrs,  on  good  soil ;  hence  we  may  safely  rely  on  a  continu- 
ance of  a  supply.  This  circumstance,  coupled  with  the  favor 
with  which  mixed  bark  tannages  are  regarded,  leaves  no 
doubt  that  for  all  time  we  shall  have  a  full  supply  of  oak 
bark.  Indeed,  it  has  been,  estimated  that  more  oak  tannin  is 
now  on  the  trees  of  Ulster  and  Greene  counties  than  there 
was  twenty  years  ago.  Although  this  reproducing  quality 
does  not  belong  to  hemlock  trees,  yet,  in  such  abundance 
are  they,  both  in  New  York  and  Pennsylvania,  that  many 
hundred  years  must  pass  before  they  become  extinct. 

The  curing  of  oak  bark  is  an  important  subject,  and  is  but 

little  understood — or,  if  understood,  is  but  poorly  attended . 
11 


162  THE   LEATHEE  MANUFACTURE. 

to.  Fully  one-third  of  the  strength  is  lost  in  the  careless 
cure,  exposure  to  wet  weather,  piling  damp,  etc.  The  English 
pay  as  much  attention  to  the  cure  of  their  bark  as  to  that  oi 
their  hay.  The  damage  to  oak  bark,  from  improper  exposure, 
is  quite  as  ruinous  as  to  hay,  and  yet  our  bark  peelers  give 
the  bark  only  as  much  attention  as  their  leisure  will  permit. 
The  substitutes  for  hemlock  and  oak  bark — the  two  prin- 
cipal agents  used  for  tanning  in  this  country — are  very  nu- 
merous. 

Gambier,  or  terra  japonica,  stands  first  and  most  prominent 
among  the  substitutes  for  bark,  both  in  England  and  here. 
In  1840  the  first  "terra"  was  used  in  America,  and  only 
in  small  quantities,  a  few  bales  then  sufficing  to  supply  the 
market;  now  the  import  amounts  to  thousands  of  tons  annu- 
ally, and  its  use  extends  to  all  the  northern  Atlantic  cities, 
Newark,  N.  J.,  and  Danvers,  Mass.,  being  the  largest  con- 
sumers. 

By  a  decision  of  the  United  States  Treasury  Department, 
gambier,  catechu,  cutch,  and  terra  japonica,  are  all  considered 
in  commerce  as  essentially  the  same,  but  while  they  all  come 
Bunder  the  common  name  of  terra  japonica  or  gambier,  a 
preparation  of  catechu,  there  are  three  different  kinds  of 
•gambier,  (in  bales,  cubes  pressed,  and  cubes  free),  all  of 
"which  differ  in  price  from  each  other,  and  from  what  is 
known  as  cutch.  The  supply  comes  almost  entirely  from 
'Singapore,  in  the  East  Indies,  that  island  having  become 
an  entrepot  in  which  are  collected  for  exportation  the  pro- 
ductions of  Cochin  China,  Siam,  the  Malayan  peninsula,  and 
the  whole  region  of  the  Eastern  Archipelago,  from  Sumatra 
to  the  meridian  of  New  Guinea  and  the  Phillipines. 

The  product,  as  we  receive  it,  is  extracted  from  the  leaves 
of  e,  species  of  acacia,  those  from  different  parts  of  India 
^giving  slight  variations  in  the  quality.  The  shrub,  or  bushy 


THE   LEATHER  MANUFACTURE.  163 

tree,  is  grown  from  slips  or  cuttings,  on  plantations.  It  is 
cultivated  and  manufactured  on  land  leased  from  the  various 
Rajahs.  The  shrub  is  allowed  to  grow  for  the  term  of  two  or 
three  years,  till  it  attains  the  size  of  dwarf  pear  trees,  when 
they  commence  to  strip  the  leaves,  stripping  at  all  seasons  of 
the  year  thereafter,  for  five  or  six  years,  until  the  soil  is  ex- 
hausted ;  the  leaves  t  come  thickly  on  the  long,  drooping 
limbs,  which  grow  outward  and  downward  from  the  ground 
to  the  top.  The  leaf  is  in  shape  like  the  mulberry,  but  is 
thick  and  gummy  to  the  touch.  The  production  can  be  in- 
creased to  any  extent,  and  would,  probably,  if  a  long  ruling 
of  high  prices  should  warrant  it.  The  cost — the  ground  rent 
being  nominal — is  the  labor,  fuel  and  transportation,  at  the 
plantation  not  over  Ic.  to  l|c.  per  pound. 

The  leaves  are  boiled  to  extract  the  gambier ;  when  re- 
duced to  the  thickness  of  molasses  the  leaves  are  raked  out, 
being  used  for  a  land  dressing  about  the  pepper  trees  ;  the 
water  is  then  evaporated  from  the  gambier  by  placing  it  in 
pans  and  exposing  them  to  the  heat  of  the  sun ;  later,  after 
drying  the  gambier  in  these  pans,  it  is  cut  into  squares,  form- 
ing cubes,  which,  when  dry  enough  to  handle,  are  bagged, 
sent  to  market  (Singapore),  screwed  into  bales  of  266  pounds, 
matted,  covered  with  gunny,  and  is  then  ready  for  shipment. 

In  the  setting  out  of  the  cuttings  they  are  placed  as  near 
each  other  as  will  leave  room  for  the  shrub  to  grow.  An 
acre  will  produce  2,600  pounds  annually,  but  it  soon  runs  out 
the  soil ;  years  ago  it  was  mostly  produced  on  the  island  of 
Singapore,  but  now  very  little  is  raised  there.  There  are 
several  kinds  or  qualities,  the  Bhio  being  the  best ;  it  orig- 
inally came  in  baskets,  in  loose  cubes,  but  lately.,  like  the 
others,  comes  to  market  in  bales. 

Cutch  and  gambier  are  from  the  same  or  similar  trees,  but 
the  two  do  not  come  from  the  same  part  of  the  country. 


164  THE   LEATHER   MANUFACTURE. 

Cutcli  is  extracted  from  wood  of  tlie  larger  and  older  trees ; 
these  trees  are  not  cultivated,  but  taken  naturally,  the  heart 
cut  out,  and  from  that  the  article  known  as  cutch  is  extracted. 

But  to  pass  from  the  consideration  of  the  source  and  man- 
ufacture of  gambier,  let  us  consider  it  as  a  substitute  for 
bark.  In  its  puro  state  it  is  largely  used  for  dyeing  pur- 
poses. The  color  is  so  dark  and  unsightly  that  tanners  can- 
not use  it — unless  with  yellow  oak — without  leaving  a  very 
objectionable  color.  The  strength  of  pure  gambier  has  never 
been  appreciated  in  .this  country,  and,  probably  from  the 
consideration  above  presented  In  England,  on  the  con- 
trary, where  oak  bark  is  used  with  a  "  strong  bloom,"  the 
color  is  overcome. 

Let  me  say  here  to  the  tanners  of  our  country  that  gambier, 
in  all  its  varieties,  is  an  expensive  substitute  for  bark.  Hem- 
lock bark  at  $10  per  cord  is  as  cheap  as  gambier  at  3|  cents 
per  pound ;  and  yet  the  Newark  tanners,  with  bark  at  $9  to 
$12,  are  using  gambier  extensively,  with  the  latter  costing 
from  5  to  7  cents  a  pound.  The  same  may  be  said  of  the 
tanners  of  Danvers.  Why  this  want  of  economy?  Because 
gambier  comes  in  a  form  very  convenient  for  use — can  usually 
be  bought  in  any  desired  quantity,  at  any  season  of  the  year. 
Its  use  prevents  overcompetition  for  bark,  and  as  the  tanners 
are  not  quite  sure  that  it  costs  them  more  than  bark,  they 
keep  on  using  it,  on  the  principle  they  do  much  of  their  busi- 
ness, viz.:  "All  is  well  that  ends  well."  There  is  a  day  in  the 
future  when  all  this  blind  waste  must  give  place  to  true 
economy ;  and  when  that  day  shall  arrive,  perhaps  to  be 
hastened  by  the  substitution  of  extracts  from  the  barks  of 
our  own  forests,  then  shall  competition  from  England  be  no 
longer  feared  by  us,  but  free  trade  in  leather,  as  in  everything 
else,  shah1  best  serve  our  interests,  as  it  would  certainly  best 
comport  with  our  self-respect. 


THE   LEATHER  MANUFACTURE.  165 

The  exports  of  gambler  from  Singapore  for  the  past  sixteen 
years  have  averaged,  for  each  year,  as  follows : 

To  Great  Britain 15,818  tons. 

To  the  Continent 3,930  tons. 

To  the  United  States 4,818  tons. 

According  to  these  figures  the  amount  taken  by  the  United 
States  has  shown  very  little  variation  during  the  whole  pe- 
riod. The  amount  used  by  Great  Britain  is  supposed  to  be 
equivalent  to  about  60,000  cords  of  bark  yearly.  The  price 
in  London  is  now  from  £25  to  £32  per  ton. 

In  Great  Britain  they  have  many  other  tanning  agents  for 
their  heavy  leathers,  with  which  in  this  country  we  have  so 
little  experience  that  it  would  be  presumptuous  for  the  writer 
t  >  speak  particularly  of  them.  They  are  mainly  valonia,  divi 
divi,  inyrabolams,  etc.  When  the  English  tanner  shall  be- 
come as  communicative  as  he  is  at  present  reticent,  the 
whole  world  will  be  enlightened  as  to  the  comparative  econ- 
omy of  these  agents  with  those  in  use  with  the  tanners  of  the 
rest  of  the  world. 

Valonia  is  the  commercial  name  for  the  acorn  cups  of  an 
Asiatic  species  of  oak,  which  forms  a  very  considerable  article 
of  export  from  the  Morea  and  the  Levant.  The  cup  only 
forms  the  valonia,  the  acorn  not  being  exported.  While  kept 
dry  it  presents  a  bright  drab  color ;  exposure  to  dampness 
makes  it  black  and  destroys  its  tanning  properties.  It  is 
very  light  and  bulky,  making  the  cost  of  its  freightage  high. 
It  is  very  little  used  in  the  United  States,  but  in  England  the 
imports  are  about  4,000  tons  annually.  The  price  in  London 
is  now  from  £15  to  £18  per  ton. 

Divi  divi  is  a  pod  of  a  shrub,  a  native  of  South  America 
and  the  West  India  Islands,  the  tannin  of  which  is  concen- 
trated in  the  rind  of  the  pod,  immediately  beneath  the  epi- 
dermis ;  the  inner  portion,  including  the  rind,  is  worthless 


160  THE  LEATHER  MANUFACTURE. 

for  tanning.  The  leather  prepared  with  divi  divi  is  likely  to 
be  porous,  and  tinged  with  brown,  or  brownish  red ;  but  little 
of  it  is  used  in  this  country. 

Myrabolams  is  the  commercial  name  of  the  dried  fruit  of 
the  rnduccanna,  imported  mainly  from  the  East  Indies.  The 
imports  at  London  for  1875  were  9,800  tons,  against  11,200 
tons  in  1874,  and  4,100  tons  in  1873.  The  present  price  is 
from  £13  to  <£17  per  ton. 

In  addition  to  the  above  tanning  materials — so  largoly  used 
in  England,  and  in  combination  one  with  another  as  well  as 
with  bark — he  English  tanners  also  use  considerable  quan- 
tities of  Mimosa,  Belgium  and  Cork  tree  bark,  and  are  yearly 
taking  constantly-increasing  quantities  of  our  hemlock 
extracts. 

Sweet  fern  is  a  tanning  shrub  or  plant  found  on  the  barrens 
of  most  of  the  counties  in  the  Eastern  Sbates.  It  has  been 
extensively  used  in  England,  and  to  a  limited  extent  in  this 
country.  The  writer  has  been  reminded  by  frequent  circu- 
lars of  various  patents  granted  for  the  use  of  this  plant  for 
tanning.  After  reading  the  strong  array  of  certificates  in 
favor  of  the  excellent  quality  of  leather  made  from  "  sweet 
fern,"  by  postmasters  and  other  equally  good  judges,  he  does 
not  dare  to  question  the  value  of  such  patents.  There  is  one 
point,  however,  to  which  the  attention  of  all  experimenters 
on  these  substitutes  should  be  called.  The  question  is  not 
whether  you  can  make  tough  leather  with  "  sweet  fern,"  su- 
mac and  the  like,  but  whether  you  can  make  the  same  or 
better  weight.  Can  you  make  the  leather  with  tannin  so  that 
it  will  both  resist  friction  and  water  ?  And  more  important 
than  a1!,  will  the  cost  be  less  than  with  hemlock  bark  at  $7 
per  cord,  or  good  rock  oak  bark  at  $8  per  cord  or  ton  ? 

That  leather  can  be  made  from  sweet  fern,  sumac,  birch, 
chestnut,  willow — indeed,  almost  all  barks— and  that  various 


THE   LEATHER  MANUFACTURE.  1G7 

acids  and  salts  will  cure,  or,  if  you  please,  tan  leather,  110  ono 
at*  all  acquainted  with  the  subject  will  dispute.  Some  of  tho 
toughest,  best  working  calfskins  that  were  ever  produced  in 
our  market  were  tanned  with  birch  bark,  and  the  color,  too, 
was  good;  but  they  were  tougL  because  the  bark  liquor  was 
weak  and  the  fiber,  in  consequence,  elongated ;  the  weight 
and  general  plumpness  were  sacrificed  to  toughness.  But 
when  shoemakers,  or  even  postmasters,  certify  that  calfskins 
resist  water  better  when  tanned  by  these  processes  than  when 
tanned  by  pure  oak  or  hemlock  bark,  the  writer  is  willing  to 
believe  them  honest,  but  attributes  a  little  of  their  zeal  to 
kindness  of  heart  rather  than  maturity  of  judgment.  This 
subject  is  well  illustrated  by  repeating  a  conversation  held 
not  long  since  with  an  old  gentleman,  who  prided  himself  on 
knowing  "a  little  about  leather,"  as  on  other  subjects  he  was 
wise.  He  said  he  always  bought  his  calfskins  of  the  "  Shak- 
ers," for,  said  he,  "  they  tan  without  steam,"  and  "  when  my 
boots  are  made  of  their  lightest  calf,  I  can  wade  all  winter 
through  snow  and  water,  and  do  not  have  even  damp  feet." 
The  old  gentleman  meant  to  tell  the  truth,  but  probably  he 
had  not  been  in  the  snow  and  water  without  rubbers  for 
years.  Yet  he  succeeded  in  his  purpose — he  entered  his 
protest  against  "steam  tanning."  It  is  thus  that  many  peo- 
ple, from  only  a  partial  understanding  of  a  subject,  are  free 
to  give  their  opinions,  upon  which  opinions  too  many,  equally 
credulous,  confide,  to  their  cost. 

Many  old-fashioned  tanners,  who  have  used  only  weak  bark 
liquor,  and  for  the  first  time  tried  terra,  are  astonished  at  the 
result.  They  tan  as  much  in  sixty  days  as  by  their  old  sys- 
tem they  did  in  six  months.  The  solution  of  the  matter  is 
plain ;  they  make  a  strong  decoction  of  the  terra,  one  that 
will  stand  20  to  25  degrees  by  the  barkometer ;  whereas,  by  the 
old  bark  process,  they  were  trying  to  tan  with  6  or  8  degree 


168  THE  LEATHER  MANUFACTURE. 

liquors.  But  let  any  tanner  take  one  hundred  pounds  of  terra 
and  dissolve  in  the  usual  way,  and  then  take  the  strength  of 
one  cord  of  good  oak  or  hemlock  bark,  and  he  will  find  the 
latter  will  tan  double  the  quantity  of  leather  that  the  former 
will. 

In  this  chapter  t^e  tanning  agents  employed  in  tawing  or 
tanning  light  leathers  have  not  been  considered.  The  omis- 
sion has  been  made  designedly,  for  the  tanning  and  tawing 
of  light  leathers  is  a  trade  by  itself,  the  treatment  of  which 
is  not  within  the  scope  of  the  present  treatise. 


OHAPTEE    XIX. 

THE    COST    OF    TANNING. 

THE    SEVEKAL    ITEMS    VARYING    WITH    DIFFERENT    TANNERS DIFFERENCES 

FROM   UNEQUAL   WEIGHT    OF    THE    CORD    OF    BARK THE    AMOUNT    OF 

TANNIN  IN  UPPER  LEATHER  AS  COMPARED  WITH  THAT  IN  SOLE  LEATHER 

COMPARATIVE   COST    IN   MAKING    HEAVY    AND    LIGHT    GAINS THE 

THEORETICAL  STRENGTH  OF  BARK  NEVER  REALIZED COST  OF  "  UNION" 

AND  OAK  TANNING ESTIMATED  COST  OF   TANNING  IN  EUROPE. 

Approximately,  the  cost  of  tanning  is  as  follows : 

Hemlock  sweat  sole  leather ^  Bb  6@  7c. 

Union  lime  sole  leather 8@  9c. 

Oak  lime  sole  leather.   ., 9@10c. 

Oak  lime  rough  leather 8@  9c. 

Hemlock  lime  rough  leather 6@  7c. 

The  varying  circumstances  under  which  the  tanners'  pro- 
fession is  pursued  will  cause  the  cost  to  differ  within  the 
limits  above  indicated.  When  a  closer  estimate  is  desired, 
giving  the  cost  of  each  department,  then  a  great  diversity  of 
opinion  prevails.  One  tanner  devotes  extra  time  to  the  beam- 
house  work ;  another  to  the  finishing ;  still  another  to  the 
handlers  or  layaways.  If  bark  is  cheap  at  one  location,  in- 
land freight  and  cartage  is  in  excess  of  that  at  another  place 


170  THE  LEATHER   MANUFACTURE 

where  bark  is  dearer ;  therefore,  in  stating  the  elements  of 
cost,  it  is  understood  that  an  average  is  struck.  These  at- 
tempted details  are  of  far  less  value  than  the  general  conclu- 
sions, which  may  be  relied  upon  as  above  stated. 

One  ton  (2,240  pounds)  of  average  hemlock  bark  will  tan 
200  pounds  of  sole  leather.  Some  of  the  exceptions  are  as 
follows :  1st.  Where  the  bark  is  ground  and  leached  imper- 
fectly, or  in  an  extraordinarily  perfect  manner.  2d.  If  the 
leather  is  tanned  with  very  strong  decoctions,  and  thereby  a 
very  large  gain  is  obtained,  as  against  weak  liquors  and  a 
light  gain.  3d.  Great  delays  and  wastes  in  applying  the 
tannin  to  the  leather — delays  which  induce  the  formation  of 
gallic  acid,  or  the  bringing  of  the  fresh,  sweet,  strong  decoc- 
tions into  contact  with  liquor  which  has  already  formed  a 
large  proportion  of  acid. 

These  exceptions  cannot  be  always  anticipated  or  known ; 
it  is  safe  to  say,  however,  that  they  vary  the  result  all  the 
way  from  180  to  200  pounds  of  leather  made  from  one  cord 
or  ton  of  bark.  If  tanners  buy  their  bark  by  the  cord,  and 
get  less  than  128  feet  solid  measure — resulting,  as  often  hap- 
pens, in  getting  1,800  pounds,  instead  of  2,240  pounds  for  a 
cord — then,  of  course,  such  tanners  will  find  the  results  of 
their  tanning  to  vary  still  more. 

Among  the  topics  above  suggested  there  is  but  one  to 
which  attention  will  be  now  specially  called,  since  on  that 
one  depends,  far  more  than  is  generally  supposed,  the  profit 
or  loss  of  the  tanner,  i.  e.,  the  strength  of  the  liquor  employed. 

The  upper  leather  tanners  of  New  England,  who  pay  from 
$10  to  $12  per  cord  for  their  bark,  claim  to  tan  and  probably 
do  tan  from  300  to  400  pounds  of  upper  leather  with  2,240 
pounds  of  bark.  If  we  comprehend  how  this  is  possible,  it 
will  enlighten  us  as  to  the  point  under  discussion.  The  up* 
per  leather  tanners  draw  their  tanning  and  coloring  matter 


THE   LEATHER   MANUFACTURE.  171 

from  agents  which  furnish  about  20  per  cent,  extractive  ma- 
terial, while  the  vigorous  sole  leather  tanner  obtains  his  cap- 
ital mostly  from  the  7  to  8  per  cent.,  tannin  which  the  bark 
contains.  The  tannin  gives  all  the  gain  added  to  the  gela- 
tine, but  the  coloring  matter  permeates  the  fiber,  while  cumu- 
lative gallic  acid  holds  it  from  decomposition.  Upper  leather, 
then,  is  not  tanned  and  filled  as  sole  leather  is,  and  to  this  ex- 
tent, and  for  this  reason,  bark  extract  will  spread  itself  over 
far  more  fiber  when  all  the  extractive  matter  is  employed, 
than  when  it  is  so  manufactured  as  to  hold  only  the  tannin 
pure  and  simple. 

The  calfskin  and  upper  leather  tanners  of  Germany,  Aus- 
tria and  Switzerland  make  fully  400  pounds  of  rough  stock 
from  a  ton  of  the  best  coppice  oak  bark,  and  where  they  use 
the  "  larch,"  corresponding  to  our  "  spruce  "  bark,  they  prob- 
ably make  about  200  pounds  (this  bark  having  less  than  half 
the  strength  of  the  former). 

If  upper  leather  and  calfskins  are  to  be  sold  by  the  pound 
(waiving  the  question  of  quality,  especially  toughness),  then 
it  is  evident  that  these  light  tannages  cannot  be  afforded. 
But  if  sold  by  measure,  then  a  light  tannage  is  profitable 
for  both  the  tanner  and  the  consumer,  under  proper  circum- 
stances. It  is  nob  proposed  here  to  discuss  the  question 
whether  a  light  tannage  will  resist  water.  A  tannage  with 
an  elongated  and  merely  colored  fiber  will  not  carry  stuffing 
when  curried  into  upper,  and  will  not  resist  dampness,  and 
for  these  reasons  such  leather  should  not  be  used  for  the 
common  wear  of  the  people,  whose  feet  are  exposed  to  the 
varying  conditions  of  the  weather  in  our  moist  and  wet  cli- 
mate. 

This  preliminary  discussion  has  been  introduced  to  solve 
the  question  as  to  whether  a  sole  leather  tanner  who  tans  by 
the  pound,  and  is  not  interested  in  the  question  of  interest, 


172  THE   LEATHER   MANUFACTURE. 

can  afford  to  make  heavy  gains  for  his  employer.  One  tan- 
ner makes  160  pounds  and  another  175  pounds  of  leather 
from  100  pounds  of  the  same  description  of  hides ;  are  they 
entitled  to  the  same  pay  per  pound  ?  Is  the  cost  to  each  pro- 
portionate? The  argument  on  the  one  side  is  as  follows  :  It 
costs  a  certain  sum  to  work  in,  handle  and  finish  a  given  lot 
leather,  whether  of  a  heavy  or  a  light  tannage ;  the  cost  of 
the  bark  being  alone  considered,  it  cannot  exceed  and  most 
usually  falls  short  of  the  price  received  for  tanning,  even 
though  that  price  is  as  low  as  six  cents  per  pound.  The 
sole  leather  problem  is,  then,  in  fact,  but  the  upper  leather 
question  over  again,  which  would  ask  and  determine  the 
following:  Can  a  tanner  afford  to  tan  rough  leather  for  less 
per  pound  than  sole  leather,  less  the  finishing?  It  is  no 
answer  to  say  they  do  tan  it  for  less,  and  it  is  not  convincing 
that  small  yards  in  old  tanning  districts,  without  much  in- 
terest to  pay,  are  still  pursuing  this  trade  successfully.  The 
argument  on  the  other  side  is  that  heavy  gains  cannot  be 
made  without  strong  liquors ;  strong  decoctions  cannot  be 
obtained  unless  more  or  less  waste  is  permitted — waste  in 
the  liquor  itself,  and  more  strength  lost  in  leaching.  Besides, 
the  actual  net  added  weight  costs  more  than  is  received, 
which  is  calculated  as  follows : 

Original  weight  of  hides 100  pounds. 

Less  hair,  grease,  flesh,  etc 15  pounds. 

Net  gelatine  and  animal  fiber 85  pounds. 

Now,  whether  this  product  is  raised  to  1GO  or  175  pounds 
is  a  question  of  mere  intrinsic  cost  of  the  pure  tannin  which 
is  capable  of  combining  with  the  gelatin^.  In  the  one  case  75 
pounds  is  required,  and  in  the  other  90  pounds.  The  cost  of 
these  resp;  ctive  factors  made  from  bark  at  $6  per  cord  would 
be  (on  the  theory  on  which  we  are  proceeding)  fully  8  cents 
per  pound,  since  in  both  cases  we  start  with  the  hide  capital 


THE  LEATHER  MANUFACTURE.  173 

of  85  pounds.  It  may  be  assumed  that  there  is  a  discrep- 
ancy between  the  theoretical  and  practical  percentage  of 
tannin  obtainable  from  bark.  "We  know  that  2,240  pounds 
of  hemlock  bark  will  make  only  200  pounds  of  leather. 
Chemists  tell  us,  however,  that  there  is  8  per  cent,  tannin  in 
this  bark ;  consequently  there  is  in  this  ton  of  bark  156  80-100 
pounds,  which,  combined  with  85  pounds  of  gelatine,  should 
give  241  80-100  pounds  of  leather.  What  has  become  of  this 
71  pounds  of  lost  tannin?  When  any  tanner  will  practically 
solve  this  doubt,  then,  and  not  until  then,  will  the  main 
question  be  answered.  Practically,  the  cost  of  a  pound  of 
tannin  is  from  6  to  8  cents,  and  not  3  to  4  cents,  as  is  gen- 
erally supposed. 

There  is  another  subject  nearly  allied  to  the  cost  of  bark, 
and  that  is  the  intrinsic  cost  of  the  oil  put  on  sole  leather. 
If  the  oil  added  gave  full  weight,  then  it  could  easily  be  de- 
termined whether  it  was  profitable  for  the  tanner  to  put  on 
much  or  little  oil.  But,  like  the  tannin  just  considered,  there 
is  much  evaporation  and  loss,  and  the  extent  of  interest  in 
the  final  result  of  weight  and  profits  must  determine  whether 
the  tanner  can  afford  to  put  oil  on  his  sole  leather  at  all,  and 
to  what  extent. 

The  cost  of  administration  in  a  tanning  establishment  is 
always  underestimated,  and  from  this  source,  in  the  writer's 
judgment,  many  of  the  discrepancies  result.  A  story  is  told 
of  a  young  man  who  left  his  father's  home  to  reside  in  the 
city  of  New  York,  promising  to  keep  an  accurate  account  of 
his  expenses,  and,  with  all  his  care,  he  found  himself  over- 
drawn more  than  $100  at  the  end  of  the  year.  To  the  in- 
quiry from  his  father  as  to  the  cause  of  this  discrepancy,  he 
said  it  must  be  "  litterateur."  The  incidental  expenses  of  a 
tanning  establishment  are  not  less  difficult  to  define.  If  an 
attempt  were  made  to  properly  apportion  each  item  of  ex- 


174  THE  LEATHEE  MANUFACTURE. 

pense  in  the  production  of  leather,  the  factors  of  the  total 
cost  would  be  about  as  follows  : 

Cost  of  bark  (hemlock)  per  3b  .................  .....  He. 

Cost  of  soaking,  milling,  sweating  and  beam  work  .  .  Ic. 
Yard  work,  including  handling,  laying  away,  etc  ....    Jc. 

Finishing,  including  drying,  rolling,  etc  ............    Jc. 

Insurance,  interest  on  tanning  and  bark  ...........    |c. 

Freights  to  and  from  the  market  ..................  Ic. 

Administration  .................................     c. 


Total  ......................................  7c. 

The  cost  of  union  or  pure  oak  tanning  will  vary  consid- 
erably from  that  of  hemlock  tanning  where  the  hides  are  un- 
haired  by  sweating,  for,  besides  the  added  cost  of  bark,  the 
extra  care  throughout  the  whole  process,  including  the  labor 
expended  in  the  preparation  of  the  hides,  that  are  mostly 
green  or  green  salted,  will  make  up  the  difference,  and  the 
cost  of  the  several  kinds  may  be  considered  as  stated  at  the 
head  of  this  chapter. 

After  the  most  diligent  inquiry  the  writer  has  found  it  im- 
possible to  even  approximate  the  cost  of  tanning  in  the  prin- 
cipal nations  of  Europe.  A  London  tanner  in  1873  estimated 
his  tanning  to  cost  12  cents  per  pound  in  bark,  and  10  cents 
per  pound  in  terra  japonica  and  valonia,  but  confessed  that 
it  was  only  an  estimate.  More  recently  a  Bristol  tanner  cal- 
culated the  cost  of  his  pure  bark  tanning  at  15  cents  per 
pound,  and  even  this  is  probably  only  an  estimate.  The 
cost  of  coppice*  oak  bark  in  the  most  favored  locations  is 
net  less  than  $25,  gold  ;  and  in  most  sections  of  Europe  it 
runs  up  to  $30,  and  even  $40,  per  ton.  On  light  tannages 
no  doubt  this  bark  will  go  a  great  way,  but  on  butts  and 
bends  it  may  be  assumed  that  foreign  tanners  use  liquors 

*  "  Coppice  "  bark  is  from  small  trees,  too  small  for  timber,  say  six  to  eight  inches 
in  diameter  ;  also  from  limbs,  equal  to  our  "  second  growth  "  bark. 


THE  LEATHER  MANUFACTURE.  175 

of  the  highest  strength.  This  is  particularly  true  of  the  tan- 
ners of  Great  Britain  ;  perhaps  it  is  not  true  to  the  same  ex- 
tent of  tanners  on  the  Continent  of  Europe. 

The  cost  of  all  other  material,  including  labor,  is  not 
greatly  different  in  Europe  from  the  cost  here.  The  tanners 
of  Great  Britain  pay  about  $1  per  day  for  their  average 
hands,  while  in  other  countries  they  pay,  according  to  a  re- 
cent authority,  about  80  cents.  But  it  may  be  fairly  ques- 
tioned whether  our  labor  is  not  more  effective,  especially  in 
view  of  the  increased  amount  of  labor-saving  machinery 
which  we  employ  over  some,  if  not  all  of  our  competitors. 


CHAPTEE    XX. 
QUICK  TANNING  PROCESSES. 

COMMON  ERRORS  OF  THOSE  OUTSIDE  OF  THE  TRADE HOW  WORTHLESS  PAT- 
ENTS   ARE    MULTIPLIED EXPERIMENT    IN   TANNING   BY    HYDROSTATIC 

PRESSURE VACUUM    TANNING — DIFFICULTIES   ATTENDING  THIS  METH- 
OD  HOW    AGITATION    OF     THE    FIBER   FACILITATES    THE    PROCESS A 

GENTLE     MOVEMENT,    WITH     OCCASIONAL    REST,    MOST    EFFICACIOUS 

.  TANNING  VS.  TAWING. 

It  is  noticeable  that  most  of  the  attempts  to  substitute  new 
for  old  methods  of  tanning  are  made  by  men  outside  of  the 
trade.  Very  few  of  the  new  inventions  for  tanning,  particu- 
larly those  that  contemplate  the  saving  of  time,  originate 
within  the  trade  itself.  The  inspiration  of  all  this  solicitude 
on  the  part  of  the  outside  world  seems  to  come  from  the  idea 
that  tanning  is  a  slow  and  tedious  process,  which  needs  in- 
vigoration  by  the  genius  of  inventors  and  men  of  thought. 
They  have  "read  history,"  in  which  it  is  claimed  that  seven 
years  is  the  allotted  time  to  tan  butts  and  bends  and  make 
good  leather,  and  that  in  this  country  we  have  only  improved 
on  this  time  by  the  introduction  of  "  steam "  and  other 
"  forcing  expedients,"  which  render  the  leather  products  here 
much  less  valuable  than  in  Great  Britain. 

There  is  DO  topic  which  requires  more  vigorous  treatment 
than  this,  not  only  for  the  good  of  the  trade,  but  for  the  ben- 
efit of  that  large  and  unfortunately  increasing  class  of  men 
who  desire  to  get  a  living  by  their  wits  and  without  labor. 


THE   LEATHER   MANUFACTURE.  177 

As  it  is  now  our  Patent  Office  gives  encouragement  to  this 
class  of  parasites,  for  there  seems  to  be  no  claim  for  im- 
provement too  absurd  to  receive  favor,  and  patents  are  mul- 
tiplied to  such  an  extent  that  no  man  can  keep  an  account 
of  them.  There  are  at  present  more  than  twenty  patents  for 
unhairing  hides  with  alkalies,  when  the  process  of  taking  off 
the  wool  from  the  sheep  and  the  hair  from  the  deerskin  by 
hard  wood  ashes  is  older  than  our  civilization.  What  is  most 
urgently  needed  in  our  Patent  Office  is  at  least  one  Examiner 
that  has  practical  knowledge  of  the  tanner's  art.  Such  a  se- 
lection it  is  not  unreasonable  to  ask,  when  it  is  considered 
that  this  manufacture  stands  second  in  importance  among 
the  industries  of  the  country.  Proper  discrimination  would 
greatly  aid  improvements,  while  our  present  system  confuses 
and  retards  meritorious  inventions. 

Among  attempts  to  facilitate  the  tanning  of  leather,  per- 
haps no  method  or  device  has  been  more  seductive  than  the 
forcing  process  known  as  the  "  vacuum  "  method.  It  is  be- 
cause of  its  specious  character  that  attention  is  here  given  to 
the  details  of  its  history  and  failure.  Hydrostatic  power  gave 
birth  to  the  first  idea  of  tanning  by  pressure.  "  If,"  said  a 
student  at  school,  "I  can  raise  myself  with  one  quart  of  water, 
by  means  of  a  hydrostatic  bellows,  that  principle  can  be 
availed  of  to  force  tannin  into  the  pores  of  a  green  hide," 
and  so  the  experiment  was  tried,  in  the  following  manner : 
A  keg  of  very  strong  construction  was  procured,  and  a  tin  tube 
one  inch  in  diameter  was  run  up  through  the  lofts  of  a  tan- 
nery to  the  hight  of  thirty  feet ;  the  keg  was  filled  with  strong 
tan  liquor,  after  a  green  prepared  calfskin  had  first  been 
placed  in  it,  and  then  the  tube  was  screwed  on  to  the  socket 
and  also  filled  with  liquor.  The  young  tanner  student  had 
the  satisfaction  of  seeing  the  liquor  forced  through  the  joints 
of  the  keg,  and  finally  the  keg  itself  burst,  by  the  hydraulic 

12 


178  THE  LEATHER  MANUFACTTTKF. 

pressure  caused  by  this  small  tube.  When,  however,  the 
keg  was  burst  open,  the  skin  was  found  to  be  only  colored, 
and  the  fiber  no  more  permeated  by  the  tannin  than  it  would 
have  been  if  the  skin  had  been  thrown  into  an  ordinary  vat 
of  liquor  for  the  same  length  of  time.  This  experiment  was- 
repeated  several  times,  for  a  longer  period  in  each  case,  by 
applying  the  power  more  gradually ;  but  the  result  each  time 
was  the  same.  Tan  could  not  be  forced  into  the  pores  of  the 
skin  by  surrounding  it  with  liquor  under  heavy  hydrostatic 
pressure. 

The  next  experiment  tried  by  this  young  student  was  to 
take  a  piece  of  prepared  hide  and  place  it  under  the  exhaust 
pump.  He  had  seen  eggs  expand  and  burst  in  a  receiver,  on 
-exhausting  the  air  which  surrounded  them.  He  had  seen 
meat  and  dead  animals  expand  and  swell  almost  to  bursting 
under  a  similar  operation,  and  so,  he  reasoned,  if  he  could 
place  a  hide  in  that  condition,  and  produce  that  effect,  and 
could,  at  the  moment  of  the  expansion,  let  in  tan  liquor — the 
Tesult  must  be  to  force  the  liquor  into  the  most  interior  cell 
of  the  hide,  and,  as  Sir  Humphrey  Davy  had  demonstrated 
that  tannin  and  gelatine,  when  brought  into  contact,  would 
iDoth  mechanically  and  chemically  unite,  he  reasoned  that 
such  process  of  exhaustion  of  the  air  and  swelling  of  the  fiber 
•must  result  in  immediately  tanning  the  hide,  on  the  admission 
of  the  tan  liquor.  But  such  was  not  the  result.  The  hide 
did  not  swell  like  other  animal  substances  filled  with  air.  He 
found  that  'the  cells  of  the  hide  were  filled  with  water,  and 
that  water  would  not  expand  in  any  perceptible  degree  on 
;account  of  the  exhaustion  of  the  air. 

A  few  years  later  an  English  engineer,  who  had  through 
many  years  of  his  professional  life  practiced  the  art  of  pre- 
serving wood  by  kyanizing  with  appropriate  chemical  agents, 
conceived  the  idea  of  coming  to  this  country  and  tanning 


THE  LEATHER  MANUFACTURE.  179 

leather  on  this  vacuum  or  kyanizing  principle.  He  spent  his 
entire  accumulations,  amounting  to  over  $10,000,  in  con- 
structing a  large  iron  tank  in  the  shape  of  an  egg,  and  lined 
this  vat  with  copper.  This  tank  was  capable  of  holding  one 
hundred  heavy  butts,  and  of  resisting  a  pressure  of  one  hun- 
dred pounds  to  the  square  inch.  He  provided  himself  with 
very  substantial  pumps  to  exhaust  from  this  tank  all  the  air, 
even  to  the  extent  of  making  almost  a  perfect  vacuum,  and 
other  pumps  to  force  in  liquor,  until  he  had  obtained  a  pres- 
sure of  100  pounds  to  the  square  inch.  Between  these  butts 
he  had  placed  cocoa  matting,  so  that  there  should  be  a  per- 
fect circulation  of  liquor.  In  short,  he  prepared  himself 
with  every  facility  which  money  could  procure  to  tan  butts 
in  a  large  and  practical  way  by  the  exhaust  or  vacuum  pro- 
cess, and  after  repeated  attempts  he  failed  entirely.  What 
induced  him  to  abandon  his  cherished  enterprise  was  a  small 
incident,  which  may  throw  light  upon  the  subject  for  the 
benefit  of  those  who  yet  see,  or  think  they  see,  a  defect  in 
his  method.  In  placing  his  butts  in  this  egg-shaped  vat,  he 
found  a  space  at  the  top  which  he  could  not  fill  with  leather, 
and  he  placed  there  several  blocks  of  seasoned  wood,  one  foot 
square.  When  his  experiment  had  ended  and  failed,  after 
many  anxious  hours  and  days  of  trial,  he  found  the  wood 
perfectly  saturated  and  tanned,  but  his  butts  were  only  col- 
ored through  the  grain.  His  conclusion  was  that  the  force 
that  will  kyanize  wood  will  not  tan  leather. 

The  name  of  the  engineer  was  Thomas  T.  Ferguson,  and 
the  place  where  the  experiment  was  tried  was  Sparrow- 
bush,  Orange  County,  N.  T.  The  full  details  of  the  experi- 
ment were  published  in  the  SHOE  AND  LEATHEK  KEPORTEI 
some  years  since,  it  having  been  made  about  the  year  1855. 
Mr.  Ferguson  obtained  patents  in  Great  Britain  and  France, 
and  applied  for  a  patent  here,  but  was  so  discouraged  by 


180  THE  LEATHEK  MANUFACTURE. 

this  effort  as  to  abandon  all  further  attempts  at  quick  tan- 
ning. 

After  these  experiments  had  been  tried  and  published  to 
the  world  there  came  another  experimenter,  this  time  with 
an  indorsement  of  a  patent,  by  which  leather  was  to  be 
tanned  in  wooden  tanks  or  vats  that  were  far  inferior,  both 
in  strength  and  construction,  to  the  plan  of  the  English  en- 
gineer just  mentioned,  and  many  tanners  have  been  induced 
to  invest  in  the  new  process.  So  far  as  is  known,  however, 
the  new  quick  tanning  process  has  been  a  failure,  and  it 
stands  so  confessed  by  those  most  interested. 

The  rationale  of  this  whole  matter  of  tanning  by  pressure 
from  both  surfaces  has  heretofore  been  greatly  misunder- 
stood. The  term  "both  surfaces"  is  used,  for  it  is  conceded 
that  if  force  is  applied  to  one  side,  and  that  the  flesh  side, 
the  tan  liquor  will  very  readily  pass,  and  tan  the  fiber  with 
which  it  comes  into  contact.  This  is  notably  shown  in  the 
tanning  of  morocco  and  light  leathers  generally.  A  goat  or 
sheep  skin  sewed  up  and  filled  with  tan  liquor  will,  by  the 
gentle  pressure  of  its  own  weight,  tan  in  a  few  hours.  A 
calfskin  sewed  up  and  placed  where  the  keg  was  placed  in  the 
student's  first  experiment  will  tan  in  a  few  moments — that 
is,  tan  liquor  will  be  forced  through  the  skin,  and  the  whole 
fiber  will  become  colored,  and  even  tanned.  But  it  must  be 
acknowledged  that  this  pressure  from  one  side  is  quite  a  dif- 
ferent thing  from  equal  pressure  from  both  sides  at  the  same 
moment.  Water  or  fluids  of  some  kind  fill  the  pores  of  the 
skin  or  hide,  and  these  are  not  compressible,  and  in  this 
lies  the  solution  of  these  repeated  failures.  Water  may  be 
expanded  by  heat,  but  it  cannot  be  perceptibly  compressed 
by  mechanical  force  or  power. 

What  would  be  the  effect  of  forcing  tan  liquor  from  both 
surfaces  into  a  hide  that  had  no  moisture  or  water  in  its 


1     THE  LEATHER  MANUFACTURE.  181 

fiber?  Simply  to  "  tan  in  "  just  so  far  as  there  was  tannin  to 
combine  with  the  gelatine,  while  the  water  in  the  liquor 
would  pass  on  and  fill  the  inner  portion  of  the  hide ;  and 
then,  before  the  process  could  be  repeated,  this  water  would 
be  required  to  be  pressed  out  by  mechanical  power  or  dried 
out  by  exposure  to  the  atmosphere — and  this  alternate  dry- 
ing and  pressing  process  would  be  so  tedious  and  withal  so 
disturbing  to  the  fiber  that  it  would  prove  impracticable. 

It  is  not  claimed  here  that  under  the  recent  vacuum  pro- 
cess, so  called,  quicker  time  has  not  been  made  than  by  the 
older  methods.  The  more  frequent  renewals  of  the  liquors, 
the  greater  activity  in  handling,  the  agitation  of  the  fiber 
occasioned  by  the  alternate  pumping  out  of  the  air  and  forcing 
in  the  liquors — these  causes  would  naturally  shorten  the  pro- 
cess, and  are  in  themselves  quite  sufficient  to  account  for  the 
more  rapid  action  of  the  tannin  in  combining  with  the  gela- 
tine of  the  hide.  But  if,  notwithstanding  these  experiments 
and  warnings,  tanners  will  insist  on  paying  their  money  for 
patents  that  are  worthless,  no  one  should  be  held  responsible, 
but  our  lunatic  asylums  should  be  enlarged. 

The  supplement  to  lire's  Dictionary  of  Arts  and  Manufac- 
tures, at  page  1044,  contains  an  account  of  an  invention  for 
tanning  in  vacuo,  patented  by  M.  Knoederer,  in  Bavaria, 
which  should  be  read  by  all  persons  contemplating  further 
efforts  to  avail  themselves  of  this  vacuo  principle  in  tanning. 
The  account,  apparently,  is  simply  a  statement  made  by  the 
patentee  as  to  his  claim,  and  the  results.  There  is  nothing 
in  either  that  is  worthy  of  serious  consideration,  except  from 
the  fact  that  the  account  has  a  prominent  position  in  a  work 
of  very  high  authority  on  general  mechanical  subjects,  and 
for  this  reason  it  attracts  attention.  It  is  noticeable  that  in 
this  process  the  sides  or  skins  are  passed  under  a  mechani- 
cal press  before  they  are  put  into  the  vacuo  vessel.  In  this 


182  THE   LEATHER   MANUFACTURE. 

manner  of  preparing  the  stock,  concession  is  made  to  the 
i'act  that  water  cannot  be  compressed. 

The  writer  has  not  desired  to  inveigh  against  the  process 
of  tanning  by  vacuum.  If  he  had  wished  to  show  the  com- 
parative expense  of  this  method  he  would  have  gone  into  a 
calculation  of  the  cost  of  the  vats  and  machinery  necessary 
to  carry  on  such  a  system,  giving  the  experience  of  some  of 
those  who  have  tried  it — which  shows  that  the  vats  made  of 
plank  and  timber,  and  exposed  to  the  air  on  their  whole  in- 
ternal and  external  surface,  will  decay  in  three  years  to  such 
an  extent  as  to  require  renewal — and  so  far  as  is  known  most 
of  those  who  have  tried  the  process  have  not  renewed  their 
vats  after  the  first  set  has  given  out. 

One  of  the  most  noticeable  defects  of  vacuum  tanning  is 
one  that  has  been  experienced  in  tanning  by  suspension  in 
the  ordinary  open  vats.  The  leather  is  "  baggy  " — that  is, 
the  nerve  of  the  hide  is  tanned  in  its  normal  condition,  and 
the  shape  of  the  animal  from  which  the  hide  or  skin  was 
taken  is  approximately  preserved.  To  overcome  this  defect 
it  has  been  the  custom  of  those  tanners  who  tanned  sole 
leather  by  this  method  to  take  the  sides  out  of  the  vacuum 
vat  and  lay  them  away  in  the  ordinary  manner  for  a  month 
or  more. 

Whether  sole  leather  is  tanned  by  suspension  in  a  vacuum 
or  oidinnry  vat,  the  experience  is  that  a  much  finer  offal  is 
produced  than  results  from  the  ordinary  handling  and  laying 
away.  But  the  leather  is  neither  so  plump  nor  free  from 
"  bag  "  as  if  tanned  in  the  usual  way. 

It  is  claimed  that  ordinary  slaughter  sole  leather,  weighing 
eighteen  pounds  per  side,  can  be  struck  through  in  from  fif- 
teen to  twenty  days,  if  vigorously  attended  to,  under  the 
vacuum  process.  The  leather  is  then  taken  out  and  laid 
away  for  thirty  or  forty  days,  when  it  is  ready  to  finish.  In 


THE  LEATHER   MANUFACTURE.  183 

making  this  statement,  and  conceding  all  that  is  here  claimed, 
what  is  the  gain,  either  in  time  or  quality?  In  ordinary  tan- 
ning a  daily  strengthening  and  handling  will  bring  this  same 
leather  through  in  sixty  d  <ys,  without  the  violent  agitation 
and  expense  attending  this  forcing  process,  and  with  better 
color  and  plumper  fiber. 

The  innovations  upon  old  methods  of  tanning  take  upon 
themselves  two  general  forms.  They  are  either  physical  and 
outward,  or  chemical  and  latent.  Of  the  former,  pressure, 
either  with  or  without  the  aid  of  the  vacuo  principle,  has  the 
greatest  number  of  advocates.  All,  or  nearly  all,  the  chemi- 
cal agents  employed  in  the  shortening  of  the  process  turn 
out  to  be  the  old  methods  of  tawing  rather  than  tanning. 

It  is  noticeable  that  even  the  vaeuo  principle  is  greatly 
aided  by  the  agitation  of  the  fiber,  for,  by  reference  to  the  ex- 
periments of  Knoederer,  it  will  be  seen  that  he  tanned  in 
about  one-half  the  time  when  the  leather  was  agitated  in  the 
vacuo  vessel,  over  and  above  the  time  taken  when  there  was 
nothing  but  the  force  of  the  vacuum  to  hasten  the  process. 
The  results  are  reported  as  follows : 

Time  required  for  Time  required 

tanning  in  vacuo  when  motion 

without  motion.  is  employed. 

Calfskins from  6  to  11  days.  4  to    7  days. 

Horse  hides  35  to  40  days.  14  to  18  days. 

"Light  cow 30  to  35  days.  12  to  16  days. 

Cow  hides,  middling. .  .40  to  45  days.  18  to  20  days. 

Heavy  cow  hides 50  to  60  days.  22  to  30  days. 

Ox  hides,  light 50  to  60  days.  20  to  30  days. 

Ox  hides,  heavy 70  to  90  days  35  to  40  days. 

Thus  it  will  be  perceived  that  motion  or  agitation  of  the 
fiber  is  a  most  essential  promoter  of  quick  tanning,  even  in 
vacuo.  To  this  fundamental  proposition  all  tanners  can 
readily  assent.  When  the  advantages  of  motion  or  force,  in 
the  sense  of  agitation  of  the  fiber,  are  taken  from  the  various 


184  THE  LEATHER  MANUFACTURE. 

patents  which  attempt  to  quicken  the  process  of  tanning,  it 
will  be  found  that  there  is  very  little  left  that  has  merit. 

The  writer  once  tried  the  following  experiment :  He  took 
four  veal  calfskins,  which  weighed  eight  pounds  when  green, 
and  prepared  them  for  the  liquor  in  the  usual  way.  He  then 
tied  the  skins  together  and  suspended  them  from  the  end  of 
a  spring  pole,  so  adjusted  that  they  were  covered  all  the  time 
by  the  liquor  in  the  vat.  For  the  first  few  hours  the  skins 
were  agitated  by  means  of  this  spring  pole  in  a  weak  color- 
ing liquor,  and  were  thus  progressed  from  vat  to  vat  until, 
at  the  end  of  the  first  day,  they  had  reached  a  liquor  of  16 
degrees  strength.  At  the  end  of  four  days  they  were  fairly 
and  even  fully  tanned.  This  spring  pole  was  so  adjusted 
that  a  slight  touch  of  the  hand  would  set  it  in  motion,  and 
as  each  one  who  passed  had  instructions  to  "  lend  a  hand," 
the  pole  was  kept  in  motion  almost  constantly,  with  the  re- 
sult indicated.  This  experiment  should  be  tried  by  every 
tanner.  It  will  attract  his  attention  to  a  most  important  ele- 
ment in  quick  tanning.  If  the  experment  should  prove  as 
interesting  as  it  did  with  the  writer,  it  will  lead  to  other  re- 
sults and  conclusions.  It  will  indicate  that  a  most  delicate 
touch  will  agitate  sensibly  the  fiber  throughout  the  whole 
skin  or  hide;  that  gentle  motion  is  most  efficacious,  and  that 
violent  motion  is  positively  injurious,  as  the  latter  purges  the 
cells  of  their  gelatine  and  prevents  the  plumping  and  final 
gain  in  weight. 

The  relative  influence  of  gentle  and  violent  motion  on  lea- 
ther when  in  the  handlers  has  been  demonstrated  by  the  ac- 
tion of  the  "  rocker."  Here,  with  the  most  delicate  ai^d  uni- 
form motion,  it  is  found  expedient  to  discontinue  the  move- 
ment altogether  for  a  considerable  portion  df  the  time,  other- 
wise the  sides  do  not  plump  and  take  on  a  uniform  grain, 
whereas  by  only  sufficient  working  the  most  desirable  result 


THE  LEATHER   MANUFACTURE.  185 

in  these  particulars  is  obtained.  Many  mistakes  have  been 
made,  and  much  damage  done  through  a  misunderstanding 
of  the  action  of  liquor  on  the  fiber,  according  to  this  princi- 
ple. Fifteen  or  twenty  lifts  or  turns  per  minute  are  ample, 
and  these  should  be  continued  only  about  half  the  time. 
Besides  giving  rest  to  the  fiber,  this  slow  motion  does  not,  to 
the  same  extent  that  a  quick,  violent  motion  does,  turn  up 
the  liquor,  bringing  it  into  contact  with  the  air,  thus  causing 
gallic  acid  to  form. 

These  experiments,  if  carefully  made,  will  also  convince 
the  tanner  that  the  gelatine  of  the  hide  has  such  an  affinity 
for  the  tannin  that  they  combine  much  more  readily  than  is 
supposed  ;  this  is  made  apparent  by  the  rapidity  with  which 
the  tannin  is  taken  up  while  in  the  rocker  vats.  Once  let  a 
tanner  be  satisfied  that  his  green  stock  is  hungry — constant- 
ly demanding  nourishment — but  without  the  voice  to  make 
known  its  wants,  and  his  financial  sympathies  will  hardly 
ever  allow  him  to  sleep  without  the  apprehension  that  he  is 
neglecting  his  most  vital  interests. 

Knoederer  claims,  and  with  some  show  of  reason,  that  his 
vacuo  process  prevents  the  formation  of  gallic  acid,  and  to 
this  extent  all  methods  that  tan  under  liquor,  in  such  manner 
as  to  avoid  exposure  to  the  air,  either  of  the  liquor  itself  or 
of  the  pelts  that  are  in  the  process,  should  receive  favor. 
Further  than  this,  the  method  of  "throwing  up"  the  packs, 
it  is  claimed,  presses  out  the  spent  liquor  and  prepares  the 
vacant  cells  to  receive  an  infusion  of  newly  charged  tan 
liquor.  Aside  from  the  disproportionate  labor  imposed  by 
the  old  over  the  newer  methods,  the  writer  believes  that  the 
action  of  the  atmosphere,  both  on  the  color  of  the  leather 
and  to  cause  oxidation  of  the  liquor,  must  prove  a  sufficient 
demonstration  of  its  impolicy. 

Leather  tanned  while  in  a  composed  state  (at  rest)  will 


186  THE   LEATHER   MANUFACTURE. 

have  a  firmer  texture  than  if  motion  is  used  to  aid  the  tan- 
ning. This  would  probably  be  the  testimony  of  the  butt  and 
bend  tanners  of  Great  Britain,  and  there  is  much  in  our  own 
experience  to  confirm  such  a  view  of  the  case.  But  the  ques- 
tion under  review  is  one  rather  of  time  than  of  firmness  of 
texture.  None  of  the  advocates  of  improved  forcing  methods 
claim,  so  far  as  the  writer  is  aware,  that  they  make  firmer 
leather.  They  usually  assume  to  make  better  time,  and  ex- 
ceptionally claim  better  gains.  Their  improved  g  tins  they 
estimate  to  come  from  the  saving  of  the  waste  of  the  gelatine, 
by  reason  of  its  earlier  entering  into  combination  with  the 
tannin  by  their  quick  as  against  the  older  and  slower  methods. 
The  best  experience  in  America  would  direct  that,  after  the 
hide  is  "struck  through"  by  the  most  rapid  combination  possi- 
ble, it  be  "  laid  away"  for  a  period  «>f  weeks  and  even  months 
— all  the  time  in  which  its  firmness  of  texture  will  improve. 
But  if  it  is  only  required  to  taw  (that  is,  strike  through)  the 
fiber  with  tannin  and  coloring  matter,  then  the  handling  or 
fiber  agitating  methods  are  alike  ;  for  harness,  upper  and 
even  calfskins  this  process  gives  very  fine  offal,  and  makes 
most  serviceable  wearing  leather. 

Hardly  a  month  passes  that  some  restive  spirit  does  not 
discover,  for  the  hundredth  time,  that  salt  and  some  of  the 
sulphates,  notably  the  sulphate  of  alumina,  known  in  com- 
merce as  alum,  and  potassa,  will  in  various  combinations 
tan,  or,  more  properly  speaking,  taw  or  preserve,  hides  and 
skins,  which,  after  being  "mooned,"  will  make  a  very  tough 
and  serviceable  upper  leather.  In  this  manner  glove  and 
calf-kid  leather  is  made  in  a  most  artistic  manner,  and  on  the 
Continent  of  Europe  the  latter  description  of  lea*her  enters 
very  largely  into  the  consumption  of  the  people  for  wear  in 
shoes  of  both  men  and  women.  For  dry  and  warm  climates 
hardly  anything  more  desirable  could  be  obtained,  and  as  it 


THE   LEATHER   MANUFACTURE.  187 

is  made  at  much  less  cost  than  bark  tanned  leather,  there  is 
an  excellent  reason  why  the  calf,  goat  and  sheep  skins  of 
those  countries  should  be  so  manufactured ;  but  when  these 
tawing  processes  are  applied  to  making  sole  leather  in  this 
country,  which  abounds  in  bark,  the  tannic  acid  of  which 
combines  with  gelatine,  and  is  when  so  combined  not  soluble 
in  water,  then  all  effort  in  that  direction  is  just  so  much 
wasted  force. 


CHAPTEE    XXI. 
THE  SPECIES  AND  GKOWTH  OE  HIDES. 

"  HNALTHY  "  AND  "  WELL  GEOWN  "  HIDES DIFFERENCES  IN  HIDES  AT  VA- 
RIOUS SEASONS  OF  THE  YEAR EFFECT  OF  CLIMATE  AND  FOOD  ON  TEX- 
TURE AND  GROWTH IMPROVED  BREEDS  OF  CATTLE  MAKE  HIDES  THIN 

AND  SPREADY COLD  CLIMATE  MAKES  A  COARSE  FIBER  AND  WARM  CLI- 
MATE A    FINE  TEXTURE EAST  INDIAN,  AFRICAN  AND   SOUTH  AMERICAN 

HIDES- — THE  HIDES    FROM  THE  EASTERN  AND    MIDDLE   STATES  AS  COM- 
PARED  WITH    THOSE   FROM    THE  WESTERN   PRAIRIES CARE   TAKEN  OF 

CATTLE  IN  EUROPE. 

In  a  previous  chapter  reference  was  made  to  the  structure 
of  hides,  but  for  quite  a  different  purpose  from  that  which  in- 
duces the  treatment  of  this  subject  here.  The  bison,  the  sheep, 
the  deer  and  the  goat  belong  to  species  so  different  from  the 
ordinary  neat  cattle  that  no  one  would  think  of  comparing 
their  merits  or  defects,  although  the  designation  of  "growth" 
will  apply  to  all  alike.  A  sheepskin  can  be  a  "healthy  pelt" 
and  "  well  grown  "  no  less  than  the  hide  of  the  ox  or  cow. 
In  this  chapter,  then,  will  be  considered  the  species  of  cattle 
and  their  growth,  in  the  sense  in  which  we  speak  of  health 
in  the  animal  and  vegetable  world ;  not  that  all  animals  or 
vegetables  are  alike,  but  only  that  they  have  their  distinctive 
natures,  and  are  well  or  ill  within  those  limits,  according  to 
the  seasons  and  circumstances  through  which  they  pass. 

The  English  tanner  must  be  credited  with  the  first  appli- 
cation of  the  term  "growth"  as  applied  to  hides.  He  would 


THE  LEATHER  MANUFACTURE.  180 

formerly  have  said  a  hide  is  "well  grown"  when  it  was 
healthy,  plump  and  fine — whether  it  was  a  bison  hide  from 
the  Western  plains  of  North  America,  or  a  Spanish  ox  hide 
from  the  pampas  of  South  America ;  but  from  this  original 
and  more  correct  designation  the  English  tanner  has  come  of 
late  to  speak  only  of  plump,  thick  hides  as  well  grown,  and, 
as  the  term  is  thus  used,  only  such  hides  as  are  suitable  for 
butts  and  bends  are  called  "  well  grown  hides  "  in  England. 
But,  to  use  the  term  in  a  less  restricted  sense,  the  hide  is 
well  grown  in  the  American  tanner's  view  when  it  takes  on 
its  highest  and  most  perfect  nature,  aod  then  the  designation 
applies  to  all  hides  and  skins  alike. 

We  have  spring,  summer,  fall  and  winter  hides,  and  these 
adjectives  have  to  the  tanner  a  most  distinct  and  qualifying 
meaning.  The  hides  of  all  our  neat  cattle  in  the  spring  of 
the  year  are  thin,  and  frequently  have  grub  holes  in  the 
shoulder  and  on  the  line  of  the  backbone.  In  early  sum- 
mer the  cattle  begin  to  recover,  and  by  late  in  June  they 
have  shed  their  hair,  though  while  the  hide  is  healthy  the 
full  growth  does  not  come  to  it  until  September  and  October. 
The  hides  taken  off  at  the  latter  season  are  thicker  and 
healthier  than  those  furnished  at  any  other  period.  At  the 
approach  of  cold  weather  the  hair  becomes  long,  and  the 
hide,  by  sudden  contractions  and  expansions,  loses  that  firm- 
ness so  desirable  for  butts  and  bends. 

The  influences,  also,  of  climate  and  food,  quite  independent 
of  the  health  of  the  animal,  have  a  controlling  effect  in  de- 
termining the  value  of  the  hide.  As  an  illustration  of  the 
effect  of  climate  on  the  fiber,  the  hides  from  Canada  and 
from  Russia  are  far  coarser  in  texture,  and  for  this  reason 
are  less  valuable,  than  hides  from  the  United  States.  Their 
winters  are  longer  and  much  more  severe  than  with  us.  This 
is  true  even  when  the  cattle  are  the  same  in  species.  It  is 


190  THE  LEATHER  MANUFACTURE. 

for  this  reason,  and  from  this  cause  in  part,  that  the  Spanish 
hides  of  South  America  are  better  grown,  both  in  the  Eng- 
lish and  American  sense,  than  are  the  hides  of  our  States. 
The  extremes  of  weather  we  have  are  never  experienced 
there.  The  cattle  feed  on  evergreen  pastures,  and  are 
never  housed,  as  with  us.  The  cattle  of  Texas  are  of 
precisely  the  same  species,  and  even  of  the  same  breed, 
as  those  of  Buenos  Ayres,  and  yet,  intermediate  between 
these,  we  have  the  cattle  of  the  Eio  Grande,  of  the  same 
species  but  of  a  different  breed,  whose  texture  is  far  coarser, 
showing  that  climate  and  food  cannot  wholly  control  the 
structure. 

The  improved  breeds  of  cattle  which  have  been  introduced 
both  in  Europe  and  here  have  done  just  so  much  to  make 
the  hides  thin  and  spready.  The  improvement  induces  a  thin 
skin.  A  "blooded  horse"  has  a  thinner  skin  than  the  old 
farm  or  plow  animal.  So  noticeable  is  this  that  the  English 
tanner  has  long  since  given  up  the  idea  of  getting  butt  hides 
from  domestic  cattle.  The  cattle  of  Spain  and  Portugal,  be- 
ing of  the  unimproved  original  stock,  give  the  English  tanners 
the  only  slaughter  butt  hides  they  have.  In  this  country  we 
are  fast  improving  all  the  plumpness  out  of  our  hides,  and  it 
will  be  only  a  few  years  until  we,  too,  shall  depend  upon  Tex- 
as and  South  America  for  all  our  thick  pelts. 

If  a  cold  climate  induces  a  coarse  fiber,  then  it  should  be 
true  that  a  warm  climate  makes  a  fine  texture,  and  this  we 
find  to  be  in  accordance  with  the  fact.  The  hides  of  Africa 
and  Central  America  have  a  fine  texture  beyond  any  other  of 
which  we  have  knowledge.  The  texture  is  not  seemingly 
so  much  affected  by  food  as  by  climate.  The  great  droughts 
of  these  tropical  regions  do  not  to  any  perceptible  extent 
control  the  texture,  but  they  do  affect  the  growth.  This  is 
illustrated  by  the  conceded  fr.ct  that  the  cattle  of  Texas  that 


THE  LEATHER  MANUFACTURE.  191 

are  known  to  die  of  starvation  retain  a  fine  textured  hide.  If 
it  be  said  that  the  animal  died  before  it  had  time  to  change 
the  fiber  or  texture  of  its  hide,  this  is  not  true  of  the  growth, 
for  the  hide  contracts  and  becomes  diseased  with  the  decay 
of  the  body.  The  same  is  true  of  a  murrain  calf  or  kip  skin. 
The  fiber  is  really  closer  and  finer  than  that  of  a  veal  skin. 

It  is,  then,  probably  true  that  where  the  species  and  breeds 
of  cattle  are  the  same,  food  affects  the  growth  and  climate  the 
texture,  and  the  experience  of  those  who  should  be  the  best 
judges  confirms  this  conclusion. 

The  "East "  and  "West  Coast"  African  hides  are  so  radi- 
cally different  that  it  may  be  assumed  the  East  coast  hides 
are  from  cattle  brought  from  the  Island  of  Madagascar,  and 
still  more  remotely  from  Hindostan  and  the  Chinese  Empire. 
The  hides  from  the  West  coast,  bordering  on  the  Atlantic, 
are  substantially  the  same  as  those  from  our  cattle,  only 
dwarfed  by  imperfect  food  and  culture.  Australia,  on  the 
other  hand,  shows  more  direct  signs  of  contact  with  Great 
Britain,  whose  colony  she  is.  The  cattle  and  hides  from  this 
province,  although  produced  under  the  same  climate  as  that 
of  many  other  islands  of  the  Indian  Ocean,  are  distinct  in 
character  from  all  the  rest,  and  when  made  into  leather  may 
pass  for  the  hides  of  well  grown  neat  cattle,  equal  to  those 
of  Great  Britain  or  the  United  States.  But  the  hides  from 
the  smaller  groups  of  islands  lying  in  the  same  ocean,  as 
well  as  from  China  and  Japan,  are  for  the  most  part  from 
cattle  that  are  popularly  known  as  East  India  cattle,  so  small 
in  frame  and  delicate  in  outline,  as  compared  with  our  cattle, 
a>  to  have  received  the  designation  of  "kips"  rather  than 
hides  from  full  grown  cattle,  as  they  are.  This  designation 
covers  that  large  class  of  East  India  kips  from  which  British 
tanners  make  a  most  serviceable  light  upper  leather,  and  the 
imports  of  these  kips  at  London  and  Liverpool  amount  to 


192  THE   LEATHER   MA.NUFACTURF. 

about  five  millions  yearlv.  The  cattle  from  which  tbose 
hides  are  taken  are  quite  uniform,  and  when  full  grown  about 
the  size  of  our  yearlings,  but  are  much  more  delicate  in  limb 
and  feature. 

The  part  which  this  East  India  hide  product  is  to  play  in 
the  future  supply  of  the  world  is  as  problematical  as  the 
question  which  is  now  agitating  our  country  about  the  labor 
supply  from  that  quarter.  Yvrhen  we  bring  ourselves  into  new 
and  friendly  business  relations  with  400,000,000  of  people, 
occupying  a  vast  territory,  and  with  a  diversified  climate 
and  soil,  we  may  well  hesitate  about  our  conclusions — and 
this  Centennial  year  joins  us  to  China  and  Japan  by  ties 
more  close  and  direct  than  it  has  been  the  fortune  of  any 
of  the  nations  of  Northern  and  Western  Europe  to  enjoy 
through  all  their  previous  intercourse. 

The  influence  of  climate  also  finds  a  notable  illustration 
in  the  character  of  hides  and  skins  taken  off  in  the  new 
Prairie  States  of  our  own  country.  All  concede  that  the 
species,  and  even  the  breeds,  are  the  same  as  with  us  in  New 
England  and  the  Middle  States,  and  yet  the  texture  of  their 
hides  and  skins  is  much  coarser ;  particularly  is  this  true  of 
the  calf  and  kips  of  those  States.  The  reasons  for  this  con- 
ceded fact  are  as  follows :  The  cattle  are  seldom  housed,  even 
in  extreme  winter.  The  farmers  have  no  barns,  or  even  pro- 
tecting sheds,  and  the  cold  so  overcomes  the  cattle  as  to 
seriously  affect  their  growth.  This  may  be  noticed  in  their 
calves.  A  calf  dropped  by  a  cow  in  the  Prairie  States  will 
hardly  stand  on  its  feet  until  eight  or  ten  days  old,  while  at 
the  East  they  will  caper  and  play  within  twenty-four  hours. 
The  calf  from  a  well-cared  for  cow,  at  the  East,  will  mature 
and  its  meat  may  be  eaten  in  three  or  four  weeks,  while  at 
the  West  from  six  to  eight  weeks  is  required.  This  same 
want  of  strength  and  growth  is  as  observable  in  the  pelt  as 


THE   LEATHER   MANUFACTURE.  193 

in  the  meat.  The  difference  between  the  "  drop  "  or  "  dea- 
con "  skins  of  Ohio  and  those  of  Northern  New  York  should, 
according  to  the  theory  heretofore  given,  be  in  favor  of  those 
of  Ohio,  for  there  is  fully  five  degrees  of  latitude  against 
New  York,  but  with  us  the  cattle  are  carefully  housed  dur- 
ing the  fall  and  winter  months,  and  this  care  more  than  com- 
pensates for  the  difference  in  climate,  and  results,  as  all  tan- 
nei  s  fully  understand,  in  giving  character  to  the  calf  pelts  of 
the  respective  regions. 

In  accordance  with  this  perhaps  too  hasty  conclusion  in 
regard  to  the  effect  of  care  and  culture  of  the  neat  cattle 
upon  their  offspring,  the  question  arises  whether  the  conceded 
fineness  of  texture  and  perfect  growth  of  the  German,  French 
and  Swiss  calf  may  not  in  some  measure  be  attributed  to  the 
almost  humane  care  which  is  bestowed  in  these  countries 
upon  their  domestic  animals  ?  And  if  this  fineness  of  tex- 
t'ire  extends  to  the  skins  of  the  offspring,  may  not  the  hide 
of  the  parent  animal  be  measurably  affected  ?  These  may  be 
mere  speculations,  but  they  are  based  upon  considerable  ob- 
servation, and  have  received  the  sanction  of  cattle  breeders 
of  much  renown.  The  cows  of  Holland  occupy  the  warmest 
and  best  portions  of  the  family  dwelling,  and  are  cared  for 
with  as  much  tenderness  as  any  of  the  inmates.  It  may  be 
said  of  the  domestic  animals  of  all  Central  and  Southern 
Europe  that  they  are  cherished  and  cared  for  in  a  much 
larger  measure  than  the  human  family,  supposed  to  be  their 
lords  and  masters.  May  not  this  culture  and  care  have  some- 
thing to  do  with  that  superior  growth  and  texture  which 
seems  to  characterize  their  calf,  goat  and  sheep  skins  ?  This 
discussion  may  be  too  general  to  satisfy  tanners  that  breeds, 
climate  and  food  control  the  value  and  qualities  of  hides  and 
skins,  and  yet  they  must  admit  that  the  theory  here  broached 
is  in  accord  with  common  observation. 

13 


CHAPTEK    XXII. 
FKENCH  AND  GEKMAN  CALF  AND  KIP. 

WHERE  OUR    IMPORTED    STOCK    COMES   FROM CAREFUL  ASSORTING  OF  THE 

RAW  STOCK  TO  INSURE  UNIFORMITY    IN  WEIGHT,  SUBSTANCE,  AND  GEN- 
ERAL   CONDITION SOAKING    AND    MILLING BREAKING   THE  NERVE 

LIMING BATING  AND  WORKING    OUT  LIME COLORING  AND  HANDLING 

LAYING      AWAY     AFTER    WORKING STUFFING DRYING SLICKER 

WHITENING BLACKING    AFTER    THE    STOCK    IS    CUT    OUT    USUAL    IN 

EUROPE VEGETABLE  OILS    USED  INSTEAD    OF    FISH   OILS DEFECTS  IN 

t         FOREIGN  CALFSKINS — STEADY  IMPROVEMENT  IN   AMERICAN  CALFSKINS. 

In  what  is  here  said  of  French  and  German  methods  of 
tanning  and  finishing  calf  and  kip  skins,  the  statements  may 
be  regarded  as  applying  also  to  the  production  of  this  class 
of  stock  in  Switzerland  and  Austria.  Indeed,  contrary  to 
the  general  impression  on  this  subject,  these  countries  are 
about  equally  represented  in  the  manufacture  of  this  descrip- 
tion of  light  imported  stock,  commonly  styled  by  consumers 
"  French  "  goods.  We  seldom  hear  of  "  Swiss  "  calfskins-, 
although  Mr.  Mercier,  of  Lausanne,  Switzerland,  is  the 
largest  manufacturer  sending  leather  to  this  country.  The 
common  designation  of  "  French,"  as  applied  to  all  imported 
skins,  arises  from  the  fact,  probably,  that  American  agents 
for  the  purchase  of  these  skins  reside  mostly  in  Paris,  and 
ship  largely  through  French  ports.  This  consideration  is 
important  in  this  connection  only  as  showing  that  a  charac- 
teristic and  almost  uniform  system  or  method  of  manufacture 


THE   LEATHER   MANUFACTURE.  195 

prevails  in  all  the  countries  mentioned,  and  the  goods  they 
produce  may,  therefore,  be  treated  as  one  manufacture. 

There  is  one  other  preliminary  consideration  which  should 
be  hare  sta'ted,  viz.,  only  the  best  goods  of  manufacturers  on 
the  European  Continent  are  sold  to  this  country  or  to  Great 
Britain — that  is,  only  those  parties  that  manufacture  calf 
and  kip  as  a  specialty,  and  in  large  quantities,  ever  think  of 
soiling  their  products  away  from  home.  Of  the  ten  thousand 
and  more  tanners  of  these  countries  probably  not  more  than 
fifty  find  a  market  in  the  United  States  for  any  considerable 
portion  of  their  stock.  The  local  or  country  producers  of 
calf  and  kip  in  all  these  countries  labor  under  the  same  dis- 
abilities as  do  the  large  number  of  small  tanners  in  our  own 
country.  They  are  not  able,  from  their  limited  facilities, 
either  to  obtain  skilled  labor  or  to  make  the  same  selections 
as  do  those  tanners  who  make  a  specialty  of  this  class  of 
goods,  and  do  the  business  in  a  large  way,  and  hence  it  is 
that  the  people  of  Continental  Europe  generally  wear  no  more 
artistic  calf  and  kip  than  may  be  found  in  the  shoes  made 
up  for  the  ordinary  wear  of  a  large  portion  of  our  own  popu- 
lation. 

In  respect  to  weight,  substance  and  general  condition,  the 
skillful  foreign  tanners  take  especial  pains  to  see  that  the 
skins  of  each  pack  shall  be  as  nearly  alike  as  possible.  In 
this  respect  their  practice  does  not  differ  from  the  theory  of 
our  largest  and  best  calfskin  tanners,  but  by  reason  of  the 
large  unmanufactured  stocks  which  they  usually  carry  they  are 
enabled  to  put  their  theories  into  practice  more  thoroughly 
than  it  is  possible  for  our  tanners  to  do.  Their  calfskins  are 
for  the  most  part  dried  without  salt  and  folded  on  the  back  ; 
the  selections  for  weight  are  th^n  made,  and  the  skins  are 
packed  in  bales.  This  is  done  by  the  factor  or  dealer.  When 
the  goods  reach  the  tanner  he  still  farther  assorts  and  then 


196  THE  LEATHER  MANUFACTURE. 

packs  them  away  in  cool  lofts  where  they  await  his  want?. 
How  different  these  circumstances  from  those  presented  to 
our  large  calfskin  manufacturers,  who  buy  all  their  stock  in  a 
green  salted  state  from  the  1st  of  May  to  the  middle  of  July  ! 
The  condition  of  the  green  salted  skins  as  handled  by  our 
tanners  taxes  their  best  energies ;  to  keep  them  from  salt 
pricking  and  decaying  is  very  difficult,  and  the  tanner  is 
forced  to  hurry  them  into  the  tantjiiig  process  with  indis- 
criminate haste. 

When  skins  in  all  respects  alike  go  into  the  soak,  they  are 
equally  affected  by  the  water,  and  are  ready  for  the  mill  at 
the  same  time,  thus  enabling  packs  that  are  commenced  to- 
gether to  go  through  to  the  end  without  separation  or  divi- 
sion. This  uniformity  also  greatly  aids  the  general  economy 
of  the  manufacturing  by  keeping  the  tanner  informed  of  the 
amount  of  product  which  he  is  realizing  from  his  raw  mate- 
rial, for  each  pack  or  series  of  packs  will  indicate  to  him  his 
loss  or  profit.  Aside,  however,  from  the  general  merit  of  this 
classification  at  the  start,  it  may  be  asserted  confidently  fiat 
no  tanner  can  make  uniform  and  good  stock  without  such 
selection,  even  with  the  greatest  care  in  the  after  handling. 

The  treatment  necessary  at  this  stage  of  the  process  will 
be  greatly  influenced  by  the  condition  of  the  stock.  If  the 
skins  are  green  salted,  as  with  us,  a  very  slight  milling  will 
suffice  ;  but  if  they  are  flint  dry,  as  with  some  of  our  small 
tanners,  then  they  should  be  thoroughly  softened.  But  any 
forced  softening  must  be  preceded  by  a  certain  amount  of 
soaking,  which  in  turn  will  greatly  depend  on  the  condition, 
whether  green,  green  salted,  dry  salted  or  absolutely  flint  dry. 
The  soaking  process  will,  therefore,  extend  from  a  few  hours 
to  a  few  days,  depending  upon  the  condition  of  the  skin  and 
the  s^ate  of  the  weather.  If  the  skins  are  flint  dry,  they 
should  not  be  milled  until  after  ample  soaking,  and  even  hand- 


LEATHER   MANUFACTURE.  197 

ling  i;i  the  soak;  but  the  first  milling  should  be  gentle,  other- 
wise the  grain  of  the  skin  may  be  cracked.  This  milling 
should  be  only  for  a  few  moments,  and  with  a  full  mill,  so 
that  the  large  body  of  skins  will  present  a  soft,  yielding 
mass  to  the  action  of  the  hammer,  if  the  softening  be 
accomplished  with  the  ordinary  fulling  stocks.  If  a  revolv- 
ing wheel  is  used,  then  the  same  care  is  necessary  that 
the  skins  may  not  have  too  violent  a  pounding  on  the  inside 
wooden  projections.  After  the  first  slight  milling  the  pack 
may  again  be  returned  to  the  soak  or  thrown  up  in  piles. 
The  action  of  the  water  in  the  second  soaking  will  be  much 
more  rapid,  and  great  care  should  be  taken  that  the  grain 
does  not  "  prick."  After  the  pelt  has  been  in  this  manner 
made  as  soft  as  water  and  ordinary  milling  will  accomplish, 
then  we  notice  the  first  peculiarity  in  the  methods  of  the 
French  and  German  tanners,  as  compared  with  the  practice 
here,  which  consists  in  the  thorough  breaking  of  the  nerve. 

The  nerve  to  be  broken  is  a  description  of  interlacing  fiber 
which  holds  the  animal  tissue.  This  nerve  is  located  trans- 
versely on  the  flesh  of  all  pelts.  It  may  almost  be  said  to 
make  a  part  of  the  flesh  itself,  and  lies  immediately  under 
that  loose,  fleshy  tissue  which  curriers  shave  off  before  they 
reach  the  pelt  proper,  on  which  they  form  their  waxed  sur- 
face. The  office  performed  by  this  nerve  or  tissue  is,  by  its 
contraction  and  expansion,  to  hold  the  pelt  close  around  the 
animal.  It  forces  the  pelt  to  conform  its  shape  to  that  of 
the  animal  whose  body  it  covers.  When  the  animal  is  fat 
and  well  rounded  out  it  expands,  and  when  poor,  sick, 
or  thin,  it  contracts.  It  is  this  nerve  which  induces  "bag- 
ging "  in  all  leather,  notably  in  sole  leather,  while  in  harness 
and  upper  leather,  which  is  stretched  by  shaving  and  scour- 
ing, much  of  the  contracting  force  of  this  nerve  is  destroyed. 
But  something  more  and  beyond  the  avoidance  of  "  bagging" 


198  THE   LEATHER    MANUFACTURE. 

is  required  in  the  preparation  of  cali'skins.  The  nerve  must 
be  so  completely  severed  or  broken  that  the  whole  pelt  will 
feel  not  only  soft,  but  actually  pulpy.  This  effect  can  only 
be  produced  at  present  by  hand  labor.  No  machine  has  jet 
been  devised  to  do  it,  although  it  may  be  predicted  that, 
when  the  great  utility  of  the  work  becomes  appreciated,  a 
labor-saving  machine  will  come  forth  from  the  brain  of  some 
American  to  perform  this  labor.  The  hide-working  machine 
of  Mr.  Henry  Lampert,  of  Rochester,  N.  Y.,  when  improved, 
may  answer  the  purpose,  or  suggest  the  way  to  some  other 
and  better  machine. 

If  the  skins  are  dry  or  dry  salted  there  is  no  difficulty  in 
determining  when  this  nerve  is  sufficiently  severed  ;  but  if 
they  are  g:  jen  or  green  salted,  unless  more  than  the  usual 
care  and  conscientiousness  is  exercised  on  the  part  of  the 
workman,  the  nerve  will  remain  unbroken,  and  will  hold  the 
whole  fiber  of  the  pelt  firmly  during  the  entire  after  tanning 
process,  so  that  it  becomes  difficult  if  not  impossible  ever 
afterward  to  make  a  yielding  and  elastic  substance  from  the 
skin  thus  treated. 

Assuming  that  we  have  succeeded  in  breaking  this  nerve, 
and  have  brought  the  pelt  to  a  soft,  pulpy  condition,  the 
next  process  will  be  liming  and  unhairing.  The  skin  has 
been  brought  to  a  condition  in  which  it  will  readily  take  the 
lime,  and  four  or  five  days  in  a  moderate  lime  water  will  neu- 
tralize the  animal  grease,  and  soften  and  swell  the  roots  of 
the  hair  so  that  the  latter  will  come  off  with  the  most  incon- 
siderable labor.  No  more  lime  need  be  used  than  sufficient 
to  accomplish  these  two  objects,  although  the  practice  in  this 
respect  is  not  uniform  ;  the  statement  is  made  rather  on  a 
knowledge  of  the  American  experience  than  from  personal 
observation  as  to  the  practice  of  foreign  tanners. 

When  the  hair  is  removed  the  skins  should  be  thrown  into 


THE  LEATHER  MANUFACTURE.  199 

the  mill  or  wheel  and  washed  for  a  few  moments.  If  in  warm 
weather,  water  at  a  temperature  of  60  degrees  should  be  used, 
but  if  the  weather  be  cold,  the  removal  of  the  lime  will  be 
greatly  facilitated  by  using  water  a  temperature  of  from  80 
to  100  degrees.  This  warm  water  and  milling  process  must 
be  conducted  with  judgment  and  care,  but  when  so  carried 
on  it  is  pt  rfectly  safe,  and  considerably  shortens  the  process 
of  depletion,  besides  saving  the  expense  of  other  depleting 
agents,  usually  called  "  bates."  * 

The  lime  must  be  worked  out  before  the  skin  goes  to  the 
handler.  In  the  practice  of  some  of  our  American  tanners, 
the  acid  of  the  liquor  is  relied  upon  to  overcome  a  portion  of 
the  lime  which  may  not  be  readily  removed,  very  much  as  is 
done  by  some  of  our  sole  leather  tanners  ;  but,  according  to 
the  best  French  process,  the  lime  must  be  thoroughly  worked 
out  before  the  skin  goes  into  the  handlers,  and  all  the  work- 
ing is  done  on  the  grain  rather  than  on  the  flesh  side.  The 
result  of  this  treatment  is  that  the  skin,  when  properly  pre- 
pared for  the  handlers,  is  so  depleted  that  the  pelt  of  an 
ordinary  eight-pound  green  veal  skin  can  be  drawn  through 
a  ring  two  inches  in  diameter. 

After  all  that  has  been  said  or  experienced  by  tanners,  it 
is  probably  true  that  much  depends  on  the  kind  of  liquors 
which  are  applied  in  the  handlers,  Skins  depleted  by  bates 
in  the  ordinary  way,  and,  subjected  to  sweet  liqiiors  in  the 
handlers,  will,  undoubtedly,  give  a  finer  flesh  and  a  tougher 
fiber  than  when  otherwise  treated,  but  whether  the  skin  will 
be  as  plump  and  as  full  in  the  offal  may  well  be  doubted. 
If,  however,  there  is  any  lime  left  in  the  skin,  sour  or  acid 

*  Some  of  the  best  and  largest  tanners  of  Switzerland  depend  very  largely  on 
the  sour  acid  liquors  of  the  "larch"  bark,  both  to  form  their  color  and  at  the 
same  time  deplete  the  skins.  One  of  the  most  successful  calfskin  tanners  oi.' 
{•Switzerland  told  the  writer  that  he  did  not  consider  it  safe  to  deplete  with  ordi  - 
nary  bates,  and  then  trust  to  sweet  liquors  to  color  and  tan  the  fiber. 


200  THE  LEATHER  MANUFACTURE. 

liquors  must  be  so  far  used  in  the  coloring  and  early  tanning 
process  as  to  overcome  the  last  particle  of  lime,  otherwise 
the  tanner  will  have  a  coarse  flesh  and  spongy  fiber  that  will 
not  "  carry  "  stuffing  in  the  finishing  process. 

The  methods  of  coloring  and  handling  followed  by  the  tan- 
ners on  the  Continent  of  Europe,  so  far  as  they  came  under 
the  observation  of  the  writer,  would  probably  fail  to  give  sat- 
isfaction to  American  tanners.  The  handling  there  is  done 
in  vats,  with  old  sour  liquors,  replenished  with  either  "larch" 
or  partially  spent  "  oak  "  tan  bark.  About  one-half  of  a  pack 
is  put  into  a  round  or  square  vat,  and  a  man  is  constantly 
employed  in  raising  the  skins  to  the  surface  by  means  of  a 
pole,  very  much  as  was  the  practice  of  our  tanners  fifty  years 
ago.  Other  tanners,  more  advanced  and  doing  business  in  a 
larger  way,  have  a  revolving  wheel  in  the  top  of  their  vat, 
constructed  and  operated  very  much  after  the  style  of  our 
so-called  "England"  wheel. 

The  process  of  merely  coloring  and  handling  soon  termin- 
ates, and  then  the  skins  are  paired  and  laid  away,  grain  to 
grain.  The  object  of  this  grain  to  grain  laying  away  is  two 
fold — first,  to  tan  the  skins  from  the  flesh  side  ;  and,  second, 
to  keep  the  grain  smooth  and  tough.  Both  of  these  objects 
are  accomplished  by  this  process,  and,  next  to  the  breaking 
of  the  nerve  in  the  beam  house,  this  may  be  considered  the 
most  important  innovation  upon  our  method.  The  skins  are 
paired  according  to  size,  and  carefully  laid  pate  to  pate  and 
butt  and  butt,  a  matter  which  is  not  difficult  in  a  pack  that 
has  already  been  selected  with  great  care  to  secure  uni- 
formity, in  weight  and  substance.  A  man  will  size  and  place 
these  skins  grain  to  grain  almost  as  fast  as  he  could  handle 
them  in  any  other  way.  When  so  placed  and  held  by  the 
hind  shanks  with  both  hands,  they  are  passed  to  a  man  in  a 
deep  .round  vat,  from  which  the  liquor  has  been  drawn.  This 


THE   LEATHER  MANUFACTURE.  201 

man  first  takes  a  shovel  full  of  spent  or  partially  spent  bark 
from  one  attendant,  and  then  a  pair  of  skins  from  another, 
laying  first  bark  and  then  skins,  and  thus  alternating  until 
the  tank  or  leach  is  nearly  filled,  walking  around  on  and 
packing  down  both  skins  and  bark,  taking  care  to  fill  up  all 
intervening  spaces  with  bark.  These  vats  are  usually  round, 
being  six  to  eight  feet  deep,  and  eight  to  ten  feet  in  diameter, 
about  ten  times  as  much  space  being  occupied  with  bark  as 
with  skins.  When  the  vat  is  filled  to  within  a  foot  of  the 
top,  water  or  old  liquor  is  run  on  until  a  covering  is  obtained, 
and  this  first  layaway  is  continued  for  from  ten  to  thirty 
days.  The  second,  third,  fourth,  and  even  fifth,  layaways 
follow  at  intervals  of  from  twenty  to  forty  days,  each  time, 
however,  with  more  of  an  admixture  of  fresh  strong  bark 
with  the  old  and  partially  spent  tan,  and  with  an  increased 
strength  in  the  liquor  run  on,  but  so  far  as  the  writer  has 
observed  no  new  bark  is  leached  and  the  decoction  resulting 
put  on  the  packs. 

The  result  of  this  practice  is  to  tan  or  color  through  the 
stock  in  four,  six  or  eight  months,  and  this  is  done  from  the 
flesh  side  mainly,  the  grain  of  each  skin  being  at  all  times 
covered  and  protected  by  the  grain  of  its  mate,  without  any 
bark  or  bark  liquor  intervening.  The  effect  of  this  close 
proximity  of  animal  fiber  is  to  prevent  anything  like  the 
formation  of  old  grain,  and  where  such  grain  does  form  it  is 
so  soft  and  yielding  as  to  be  readily  "  pulled  out "  or 
"  boarded  out "  without  scouring  in  the  process  of  currying. 
The  grain,  when  the  skins  are  first  separated,  indicates  just 
such  a  condition  or  appearance  as  would  the  grain  on  a  pack 
that  had  been  allowed  to  sweat  in  piles,  but  as  the  grain  sur- 
faces have  been  absolutely  excluded  from  the  air  during  the 
whole  process  they  are  without  stain,  of  the  most  delicate 
color,  and  extremely  fine  and  pliable. 


202  THE   LEATHER   MANUFACTURE. 

The  tanning  processes  being  completed,  the  bark  is  thor- 
oughly shaken  out  as  the  skins  are  taken  up  and  laid  in  piles 
to  drain  and  "sammy."  At  this  period  comes  in  the  third 
peculiarity  of  European  calfskin  tanning,  namely :  The 
skins  are  worked  over  a  small  half  round  beam,  on  the  flesh 
side,  with  an  ordinary  tanners'  worker.  The  object  of  this 
working  is  to  complete  and  make  permanent  the  work  of 
breaking  the  nerve  commenced  in  the  beam  house,  and  to 
take  off  any  flesh  which  may  remain.  Its  effect  is  to  make 
the  skin  soft  and  the  fiber  elastic,  and,  being  quite  inexpen- 
sive, should  never  be  omitted.  It  can  be  done  by  any  ordi- 
nary yard  hand  who  is  faithful  and  honest,  but  there  must 
be  no  slighting. 

One  of  the  characteristics  of  foreign  workmen  is  that  they 
are  faithful  to  instructions  ;  any  manipulation  which  requires 
patient  labor  may  be  intrusted  to  them  without  fear  of  omis- 
sion or  neglect.  So  much  cannot  be  said  for  American 
workmen,  particularly  those  who  work  by  the  piece  ;  they 
are  constantly  studying  how  to  save  labor,  and  the  tanning 
and  finishing  of  calfskins  in  a  style  as  perfect  as  are  the 
goods  of  our  European  neighbors  consists  of  so  many  little 
things — all  demanding  careful,  painstaking  labor — that, 
without  the  greatest  oversight  on  the  part  of  the  foreman,  it 
is  not  to  be  expected  that  any  large  proportion  of  really  good 
skins,  such  as  the  French  and  Germans  make,  will  be  manu- 
factured in  this  country  for  many  years  to  come. 

After  the  skins  have  been  tanned  and  "  mooned,"  as  al- 
ready indicated,  they  may  be  flesh  shaved,  as  before  de- 
scribed, or,  as  some  prefer,  they  may  be  thrown  into  the 
wheel  and  "  rough  stuffed  "  before  being  shaved.  The  latter 
method  is  regarded  as  wasteful,  since  the  shavings  absorb 
oil,  and  to  this  extent  cause  a  l^ss ;  but  many  finishers  claim 
that  a  better  flesh  is  obtained  when  the  skins  are  "  rough 


THE  LEATHER  MANUFACTURE.  203 

stuffed  "  before  the  shaving  is  done.  The  writer  prefers  the 
former  course. 

In  beginning  the  finishing  process — the  tanning  and  beam 
working  on  the  flesh  haviug  be^n  faithfully  done — there  will 
be  very  little  or  no  loose  flesh  to  shave  off,  and,  while  a 
"  smooth  face "  must  be  obtained,  it  is  desirable  that  no 
more  than  merely  the  flesh  should  be  removed  with  the 
knife  at  this  period.  From  one  to  three  pounds  per  dozen 
may  easily  be  lost  by  want  of  care  at  this  stage  of  the  pro- 
cess; therefore  this  shaving  should  never  be  done  by  the 
piece,  but  always  by  the  day,  and  with  the  most  conscientious 
workmen,  for  labor  that  is  worth  fifty  cents  per  dozen  can  be 
made  to  cost  the  tanner  two  or  three  dollars  by  the  loss  in 
weight  which  the  workman  may  cause.  If,  from  any  omis- 
sion, an  unusual  amount  of  old  grain  has  been  allowed  to 
come  into  the  grain  of  the  skins,  it  may  be  advisable  to  board 
them  to  draw  out  such  surplus  grain,  or  rather  to  scatter  it, 
while  in  this  rough  state,  but  this  necessity  will  seldom  arise 
if  proper  attention  is  paid  in  the  tanning  process. 

Assuming  that  all  leather  finishers  have  both  scouring  and 
stuffing  wheels,  it  is  recommended  that,  before  scouring  by 
hand,  the  skins  be  thrown  into  the  scouring  wheel,  and  all 
the  bloom  and  dirt  washed  out.  When  this  service  is  thor- 
oughly performed,  the  hand  labor  necessary  is  little  more 
than  that  of  striking  out  the  SKUI  on  both  flesh  and  grain 
sides. 

As  one  of  the  characteristics  of  French  finishing  is  to  leave 
all  the  "stretch"  in  the  skins  rather  than  to  take  it  out,  we 
begin  our  new  method  by  omitting  almost  entirely  the  cus- 
tomary scouring  and  distending  process.  If  the  skins  have 
been  well  "struck"  on  both  grain  and  flesh,  very  much  of 
the  old  liquor  and  water  has  been  pressed  out  of  them,  but 
yet  they  are  too  wet — the  fiber  is  too  full  of  water — to  allow 


204  THE  LEATHER  MANUFACTURE. 

tlie  oil  and  tallow  to  properly  enter,  hence  they  should  be 
partially  sammied.  This  requires  care,  otherwise  the  oil  will 
enter  unevenly  and  darken  the  grain. 

Some  curriers  have  hand  presses,  and  hydraulic  power 
presses  are  used,  under  which  the  skins  are  placed  to  force 
out  more  water  than  it  was  possible  to  press  out  with  the 
slicker,  but  the  observation  of  the  writer  is  to  the  effect  that 
exposure  to  the  atmosphere  is  the  only  proper  way  of  pre- 
paring the  skins  for  the  stuffing  wheel,  and  after  they  have 
been  thus  exposed  to  the  air  a  sufficient  time  to  fairly  stiffen 
they  should  be  taken  down  and  placed  in  piles,  as  in  this  sit- 
uation the  moisture  will  distribute  itself,  drawing  from  the 
center  to  the  circumference. 

Unless  great  care  is  observed  stuffing  leather  by  the  use  of 
the  stuffing  wheel  may  do  incalculable  damage.  French  in 
its  origin — its  present  efficiency  is  wholly  due  to  American 
adaptation.  The  oil  and  tallow  should  be  held  in  separate 
vessels,  warmed  with  a  steam  coil  at  the  bottom  of  each,  and 
thoroughly  mixed  while  in  this  warm  state.  When  the  skins 
are  properly  sammied  they  should  be  thrown  into  the  stuf- 
fing wheel,  the  proper  amount  of  stuffing  added,  and  the  wheel 
set  in  motion.  Ten  to  twenty  minutes  will  suffice  to  mill  this 
mixture  of  oil  and  tallow  into  the  skins;,  but  the  wheel  should 
be  allowed  to  run  long  after  the  stuffing  is  outwardly  ab- 
sorbed, since  this  fulling  process  will  work  the  stuffing  into 
the  center  and  thicker  portions  of  the  skins.  It  is  possible 
to  put  in  an  excess  of  oil  and  tallow,  and  this  is  quite 
common,  but  such  excess  may  be  got  rid  of  in  one  of  two 
ways,  as  follows:  First,  carefully  pile  the  skins  on  each 
other  as  they  come  out  of  the  wheel,  and  by  their  own  weight 
the  excess  of  oil  will  be  pressed  out;  or,  second,  throw  each 
skin  on  a  table  and  gently  work  out  the  excess  by  means  of  a 
steel  slicker,  using  judgment  to  press  equally  over  the  wholly 


THE  LEATHER   MANUFACTURE.  205 

grain  surface.  If  clone  with  sufficient  care,  this  action  will 
relieve  the  flanks,  pates  and  bellies  of  any  undue  proportion 
of  grease,  and  the  skins  may  then  be  hung  up  to  dry,  either 
from  tenter  hooks  or  over  sticks. 

Although  skins  freed  from  the  acid  of  the  bark  and  satur- 
ated with  oil  are  not  so  liable  to  be  affected  in  their  color  by 
means  of  light  and  air  as  ordinary  tannages,  yet  they  are 
sufficiently  so  to  require  care  in  these  respects.  The  drying 
loft  should,  therefore,  be  so  constructed  as  to  enable  the  at- 
tendant at  all  times  to  regulate  the  amount  of  light  and  air 
which  should  enter,  and  the  drying  should  be  slow.  It  will 
always  be  safe  to  allow  night  air,  which  is  without  light,  to 
enter.  In  the  winter  months  great  care  should  be  taken  to 
avoid  excessive  stove  or  even  steam  heat,  the  tendency  of  all 
artificial  heat  being  to  make  the  leather  harsh  and  bring  the 
grease  to  the  surface. 

After  the  skins  have  been  stuffed  and  dried  in  the  manner 
indicated  they  may  be  packed  away  in  piles  of  200  or  300, 
and  allowed  to  remain  for  a  great  length  of  time,  as  they  will 
improve  all  the  while.  It  is  in  this  condition  that  the  large 
stocks  of  Europe  are  carried,  goods  made  out  of  season  or 
which  are  unsalable  from  any  cause  being  thus  held  over  for 
years.  ' 

The  process  of  slicker  whitening  is  preferred  to  the  old 
method  for  three  excellent  reasons :  1.  Less  of  the  weight 
is  taken  off.  2.  A  better  (smoother)  face  is  left.  3.  A  work- 
man can  do  more  work  with  one  of  these  tools  than  with  the 
usual  whitening  knife. 

While  the  skin  is  in  the  dampened  condition,  which  has 
been  brought  about  both  for  the  convenience  and  more 
effective  work  of  the  slicker  wliiteuer,  it  is  thrown  upon  a 
table  covered  with  leather,  grain,  up,  and  by  means  of  a  long 
"grain  boarder,"  held  firmly  by  the  whole  arm,  the  entire 


206  THE   LEATHER   MANUFACTURE. 

skin  passes  under  the  operation  of  the  board,  but  especial 
attention  should  be  paid  to  the  neck  and  pate,  or  wherever 
else  an  old,  elongated  grain  may  be  seen.  The  effect  of  the 
boarding  will  not  be  to  make  the  grain  entirely  smooth,  but 
so  to  scatter  it  as  to  render  it  less  observable.  It  is  no  part 
of  the  duty  of  the  French  currier  to  make  a  smooth  grain ; 
indeed,  this  is  just  what  he  wishes  to  avoid ;  but  it  is  part  of 
his  art  to  make  a  smooth  and  fine  flesh  surface  with  a  grain 
so  loose  and  yielding  as  to  adjust  itself  readily  to  the  opera- 
tion of  the  crimper. 

Contrary  to  our  manner  of  proceeding,  the  calf  and  kip 
skins  in  Europe  intended  for  boots  are  not  blacked  on  the 
flesh  until  after  they  are  crimped  on  the  boot  trees.  They 
are  bought,  sold  and  held  in  the  "  russet "  state.  While  in 
this  condition,  (cut  in  forms),  they  are  carefully  inspected, 
and  wherever  small  cuts,  hacks  or  flaws  of  any  kind  are  ob- 
served on  the  flesh  they  are  buffed  or  shaved  out.  The  effect 
of  this  operation  is  to  make  the  skin  slightly  thinner  at  the 
defective  point,  but  in  cutting  in  forms  these  defective  spots 
are  so  located  as  not  to  injure  the  wear,  and  at  the  same  time 
to  escape  the  notice  of  the  consumer.  This  work  is  done  by 
boys  or  women,  who,  with  broken  glass  or  thin  turned  steel 
edges,  pare  down  the  lips  of  the  cuts  or  hacks  so  carefully  as 
to  hide  them  from  view.  After  this  is  done,  the  fronts  are 
blacked,  df  a  special  trade  demands  it,  but  usually  the  goods 
pass  to  the  manufacturer  in  the  russet  state,  to  be  by  him 
blacked  after  they  are  made  up. 

Before  crimping  the  boot  front,  the  grain  at  the  instep  is 
buffed  from  each  front.  The  reasons  for  this  are  as  follows : 
1st.  If  the  grain  is  left  on  the  crimp  would  pucker  it,  and 
render  it  rough  to  that  portion  of  the  foot ;  2d.  By  removing 
the  grain  the  crimp  is  effected  with  less  labor,  as  that  portion 
of  the  skin  is  made  more  elastic ;  3d.  The  tendency  of  the 


THE  LEATHER  MANUFACTURE.  207 

process  is  to  force  more  volume  of  fiber  just  at  the  turn  than 
elsewhere ;  but  4th,  and  mainly,  it  softens  the  skin  at  the 
point  where  there  is  the  greatest  friction  and  pressure  on  the 
muscles  of  the  foot.  It  is  quite  notorious  that  buffed  leather 
is  much  softer  than  that  in  which  the  grain  is  left  on,  and  it 
often  happens  that  men  with  tender  feet  require  their  calf- 
skins to  be  buffed  over  the  whole  grain  surface  before  being 
made  up.  The  reasons  for  the  practice  of  buffing  so  much 
of  the  crimped  form  as  covers  the  instep  will  therefore  ap- 
pear sensible. 

The  leather  finishers  everywhere  south  of  Great  Britain 
use  very  largely  and  quite  uniformly  the  vegetable  oils, 
mixed  with  tallow,  instead  of  the  fish  oils  used  by  us.  This 
difference  alone  is  quite  enough  to  account  for  much  of  that 
softness  and  elasticity  of  fiber  so  much  admired  in  their 
leather  product.  The  degras  of  France  is  about  the  equiva- 
lent of  the  sod  oil  of  Great  Britain  and  the  buckskin  oil  of 
America,  but  there  is  this  difference  between  them  :  Vege- 
table oils  make  the  base  of  the  degras  while  fish  oils  make 
the  base  of  buckskin  and  sod  oils.  Palm  oil  is  very  largely 
used  by  the  calfskin  manufacturers  of  France  and  Switzer- 
land ;  cocoanut  oil,  castor  oil,  cotton  seed  oil,  and,  by  parity 
of  reasoning,  linseed  oil,  may  all  be  serviceable,  but  fish  oils 
should  never  be  used.  They  cause  leather  to  gum,  and  their 
whole  nature  seems  destructive  to  the  fiber. 

Ihere  are  three  general  defects  which  should  not  be  over- 
looked in  the  French  methods  of  manufacture  : 

First — They  do  not  properly  trim  their  skins ;  the  offal 
usually  found  on  French  calfskins  is  so  thick  and  coarse  as 
to  be  perfectly  worthless.  That  a  people  otherwise  so  eco- 
nomical in  their  methods  should  have  fallen  into  this  defective 
manner  of  trimming,  if,  indeed,  it  can  be  called  trimming  at 
all,  and  continue  the  practice  for  so  many  years,  is  a  matter 


208  THE  LEATHEE  MANUFACTURE. 

of  surprise  to  all  thoughtful  persons  who  have  to  do  with 
the  manufacture. 

Second — By  the  French  method  of  tanning  and  finishing 
the  leather  made  is  less  impervious  to  water  than1  that  made 
by  either  the  English  or  American  methods,  rendering  the 
former  only  suited  to  dry  climates,  or  for  wear  in  large  cities, 
where  it  is  not  exposed  to  wet  or  damp  soils. 

Third — The  starved  nature  of  their  tannage — the  very 
effort  they  make  to  render  their  leather  soft  and  yielding  in 
texture — deprives  the  shoulders,  bellies  and  flanks  of  that 
gelatine  which,  when  combined  with  tannin,  enables  the 
manufacturer  to  cut  his  stock  to  the  very  outer  edge,  thus 
making  every  square  inch  serviceable. 

It  is  in  great  measure  from  the  want  of  fineness  in  the 
offal  of  foreign  goods  that  our  shoe  manufacturers  are  sub- 
stituting American  for  French  calf.  So  long  as  our  people 
wore  boots  the  coarse  offal  of  the  French  stock  could  be  run 
up  into  the  legs,  but  now  that  we  have  become  a  nation  of 
shoe  rather  than  boot  wearers,  the  change  has  induced  a  re- 
versal in  the  public  judgment  in  regard  to  the  economy  of 
the  French  method  of  tanning  and  finishing  calf. 

Perhaps  also  it  is  due  to  the  American  calfskin  manufac- 
turer to  concede  that  he  has  greatly  improved  in  making  a 
more  elastic  fiber,  while  he  has  retained  the  fineness  of  the 
offal  and  closeness  of  trim.  It  must  be  within  the  observa- 
tion of  all  leather  consumers  in  this  country  that  both  calf 
and  wax  upper  leather  have  undergone  a  great  change  for 
the  better  within  the  past  few  years.  A  few  more  t-tridi-s 
forward  and  the  upper  leather  of  America  will  stand  on  a  par 
with  that  of  the  best  productions  of  the  most  advanced 
nations  of  Europe. 

In  respect  to  the  proper  classification  of  skins  the  Frem  h 
and  German  tanners  have  always  had  the  advantage,  and 


THE   LEATHER   MANUFACTURE.  209 

this  is  especially  the  case  with  those  large  manufacturers 
sending  their  stock  to  this  country,  who  produce  as  many  as 
from  2,000  to  3,000  dozen  per  year,  and  in  exceptional  cases 
vastly  more.  This  enables  them  to  select  male  from  female 
skins,  and  make  several  qualities  and  selections  inside  these 
general  classes.  Until  the  calfskin  tanners  of  America  shall 
imitate  the  French  tanners  in  this  particular  they  will  labor 
under  present  disabilities,  but  the  energy  and  forethought 
which  has  brought  us  so  near  competing  on  equal  terms, 
will,  there  can  be  little  doubt,  carry  us  through  to  that 
desired  period  in  our  international  intercourse  when  our 
tanners  shall  no  longer  fear  the  effects  of  the  removal  of  all 
duties,  and  a  free  exchange  in  all  the  leather  products,  to  the 
mutual  advantage  of  all  the  nationalities  of  the  world. 


CHAPTEE    XXIII. 
GRAIN  AND  BUFF  LEATHER 

SPLITTING    MACHINES MAKING    SPLIT    LEATHERS   FROM    GREEN    HIDES    OR 

FROM  TANNED    LEATHER EVERY    KIND    OF    NATURAL    GRAIN   SUCCESS- 
FULLY IMITATED STRENGTH  AND  DURABILITY    OF    SPLIT  LEATHERS 

THEIR  INTRODUCTION    TO    EUROPEAN    CONSUMERS ESSENTIALS    TO   BE 

•  CONSIDERED  IN  THE  MANUFACTURE  OF  GRAIN  AND  BUFF  LEATHER. 

Commencing  with  the  successful  introduction  of  the  union 
splitting  machine,  about  the  year  1830,  leather  made  from 
the  hides  of  neat  cattle  has  been  split  down  to  a  compara- 
tively thin  substance,  and  the  "grain  splits"  have  been  used 
extensively  for  shoes,  as  well  as  trunks,  harness,  etc.  With 
the  improvements  made  in  that  machine  in  later  years,  very 
safe  and  good  work  has  been  done  in  splitting  the  ordinary 
cow  hides  into  both  stout  and  light  grain  leather,  while  the 
best  of  the  flesh  splits  has  been  used  extensively  for  boot 
backs  and  shoe  quarters,  and  the  middle  splits  for  trunks. 
More  recently,  or  about  1860,  the  "  endless  belt  knife  split- 
ting machine  "  came  into  use,  and  it  splits  with  even  greater 
precision  than  the  union  machine.  From  its  high  cost 
(about  $1,000),  as  well  as  from  its  complicated  structure, 
making  it  liable  to  get  out  of  order,  comparatively  few  of 
these  machines  are  in  use.  When  it  is  new  and  in  good 
order,  and  handled  by  a  competent  workman,  an  ordinary 
cow  hide  can,  with  it,  be  split  into  three,  and  even  four  dis- 
tinct parts,  with  as  great  precision  as  the  sheepskins  of 


THE   LEATHER   MANUFACTURE.  211 

England  are  split  grain  from  flesh.  The  merit  claimed  for 
this  endless  belt  machine  is  that  the  fiber  of  the  hide  is  cut 
without  strain,  while  it  is  alleged  that  with  the  union  ma- 
chine considerable  force  is  required  to  draw  the  side  through. 
This  objection  had  much  force  with  such  machines  as  were 
constructed  early  in  the  history  of  splitting  leather,  but  with 
the  improvements  since  introduced,  there  is  no  perceptible 
disturbance  of  the  fiber,  and  no  greater  power  is  required 
than  can  be  applied  with  the  attendant's  hands.  These 
union  machines  are  now  so  perfect  and  durable  in  their  con- 
struction that  they  may  be  said  to  be  indestructible  by  ordi- 
nary wear,  and,  with  average  skill  and  care,  grain  leather  of 
the  thinnest  description  can  De  split  from  the  ordinary  neat 
hide.  An  illustration  of  the  union  leather  splitter  will  be 
found  in  subsequent  pages. 

So  much  has  been  said  in  regard  to  the  machines  and 
facilities  for  spliting  that  we  may  consider  the  intrinsic 
merits  of  the  grain  and  buff  leather  which  has  for  the  past  few 
years  come  into  such  universal  use  in  this  country,  and  is 
now,  by  its  cheap  and  excellent  qualities,  commending  itself 
to  all  the  countries  of  Europe.  A  clear  distinction  must  be 
kept  up  between  the  process  of  manufacturing  these  grain 
and  buff  leathers  from  the  green  hide  and  those  made  from 
tanned  leather.  Our  curriers  are  too  often  tempted  to  split 
down  fully  tanned  leather  into  grain.  Such  efforts  bring  into 
disfavor  all  grain  leather,  since,  from  the  very  nature  of  the 
case,  the  grain  must  be  tender  when  fully  tanned  first  and 
split  afterward.  It  is  a  great  misfortune  that  grain  leather 
made  in  this  improper  manner  cannot  be  discriminated 
against  by  buyers,  as  it  is  almost  sure  to  give  dissatisfaction 
when  made  up  into  shoes ;  but,  tempted  by  a  concession  of  one 
or  two  cents  per  foot,  manufacturers  are  too  apt  to  "  try  just 
this  one  lot,"  and  that  one  lot,  however  small,  carries  dis- 


212  THE  LEATHER  MANUFACTUKF. 

credit  to  a  whole  class  of  goods.  These  objections  apply 
only  to  light  women's  grain.  Men's  boot  grain,  which  is 
split  to  weigh  seven  to  eight  ounces  to  the  foot,  will  have 
substance  enough  to  hold  against  any  strain. 

But  the  object  of  this  chapter  is  to  consider  the  intrinsic 
qualities  of  modern  grain  leather,  manufactured  in  imitation 
of  calf,  goat,  seal  and  even  hogskins.  By  far  the  largest  por- 
tion is  manufactured  as  "pebble"  or  "goat."  The  grain  is 
made  coarse  or  fine,  to  suit  the  taste  of  the  purchaser.  In- 
deed, with  present  appliances,  an  order  can  be  filled  at  short 
notice  with  just  such  devices  imprinted  on  the  grain  as  may 
be  desired,  and  without  additional  cost  to  the  purchaser. 
Probably  there  is  no  animal  that  lives  whose  skin  cannot  be 
imitated,  so  far  as  the  external  appearance  is  concerned,  and 
this  can  be  done  by  a  machine  which  will  duplicate  the  im- 
pression indefinitely.  The  effect  of  the  production  of  this 
description  of  goods  on  the  manufacture  of  goatskin  morocco 
in  Europe  is  just  beginning  to  be  felt.  In  this  country  its 
influence  has  been  very  perceptible  for  the  past  five  years. 

The  question  which  consumers  desire  to  be  satisfied  upon 
is  as  to  whether  it  is  tougli,  so  that  it  will  wear  without  tear- 
ing or  cracking.  In  respect  to  "  cracking  "  there  can  be  no 
hesitation  in  saying  that,  from  the  nature  of  the  pelt  and  its 
treatment,  it  is  not  more  liable  to  crack  than  East  India  kips, 
goat  or  seal  skins.  It  will  also  take  as  durable  a  color,  ?'.  e., 
it  will  not  turn  "  foxy."  But  is  it  as  lasting  in  general  struc- 
ture ?  Can  a  part  of  a  pelt  be  made  as  strong  as  the  whole  ? 
The  answer  is  both  no  and  yes.  In  the  bending  of  the  fiber 
of  the  leather  so  frequently  as  is  made  necessary  on  a  man's 
or  woman's  shoe,  the  stock  is  a  great  deal  more  liable  to 
crack  if  it  be  of  thick  leather  than  if  thin,  but  if  the  thin 
leather  is  made  from  a  pelt  that  has  its  whole  structure,  both 
flesh  and  grain,  and  all  intermediate  fiber,  it  must  be  more 


THE   LEATHER  MANUFACTURE.  213 

serviceable  than  when  this  structure  is  broken,  as  is  the  case 
with  these  split  grain  leathers.  But  suppose  we  admit  that 
this  grain  upper  is  Jess  tough  than  goat,  seal  or  horse 
leather,  if  it  is  sufficiently  tmigJi  to  wear  out  tivo  pairs  of  soles, 
as  is  affirmed  by  our  experience,  and  can  be  offered  at  thirty 
per  cent,  less  price  than  all  competing  leather,  then  will  it 
not  be  pronounced  a  success,  and  will  it  not  largely  take  the 
place  of  these  leathers  throughout  Europe  ?  That  it  will 
greatly  affect  the  consumption  and  price  of  goat,  calf,  seal 
and  horse  leather  throughout  the  whole  world  there  can  be 
no  doubt ;  whether  it  shall  ultimately  come  into  general  use 
for  women's  and  children's  shoes  will  depend  upon  the  hon- 
esty and  fidelity  with  which  it  is  manufactured.  It  is  now 
almost  exclusively  made  in  this  country,  and  because  we 
have  the  machines  to  split  successfully  the  hides.  When 
the  leather  manufacturers  of  Germany,  Austria,  Switzerland, 
and  even  France,  shall  turn  their  attention  to  the  production 
of  this  leather  they  will  successfully  compete.  Outside  of 
our  machines  and  our  trained  hands  for  splitting  we  have  no 
advantages  over  those  countries.  Indeed,  their  cow  hides 
are  finer  in  grain  than  ours,  and  as  their  neat  cattle  are 
almost  exclusively  cows,  there  can  be  no  reason  to  question 
a  full  supply  of  the  raw  material.  The  improved  breeds  of 
cattle  in  Great  Britain  will  also  give  the  English  tanner  a 
most  suitable  cow  hide  for  grain  upper. 

The  question,  then,  of  substituting  split  grain  for  the  skius 
of  the  smaller  animals  is  one  as  broad  as  the  two  Continents. 
In  view,  therefore,  of  the  largeness  of  the  subject,  let  us  con- 
rider  in  conclusion  some  of  the  methods  and  economies  of 
manufacturing  this  grain  and  buff  leather  for  women's  and 
children's  shoes. 

First. — The  hides  must  be  free  from  all  scratches,  and  from 
horn  and  hook  marks  on  the  grain.  Cows  sent  from  the  West 


214  THE   LEATHER   MANUFACTURE. 

on  cars  will  not  produce  hides  sufficiently  free  from  the  above 
defects  to  make  grain  leather. 

Second. — The  hide  should  not  weigh  over  40  to  45  pounds, 
cured  and  trimmed  weight.  Leather  made  from  old  and 
heavy  cow  hides  the  grain  is  coarse,  and  when  cut  down  thin 
is  tender. 

Third. — They  should  be  worked  in  when  as  fresh  as  pos- 
sible ;  hides  that  have  laid  in  the  salt  for  a  long  time  are  apt 
to  have  a  "  frized  "  grain. 

Fourth. — The  lime  should  be  worked  out  thoroughly ;  warm 
water  in  the  wheel  will  do  this  to  a  limited  extent,  but  bates 
should  be  used  as  a  last  resort  before  final  working. 

Fifth. — Our  best  grain  leather  manufacturers  handle  and 
even  tan  by  suspending  the  sides ;  this  practice  makes  the 
shoulders  and  flanks  Very  fine.  Whether  it  adds  to  the 
toughness  of  the  grain  may  be  questioned ;  but  for  buff 
leather  it  is  indispensable,  and  even  for  grain  it  presents  so 
many  advantages  that  it  may  be  doubted  whether  any  man- 
ufacturer can  afford  to  dispense  with  the  practice. 

Sixth. — The  side  is  colored  and  raised  before  splitting  ;  that 
is,  the  sides  are  handled  on  sticks  (suspended)  until  they  be- 
gin to  feel  firm  and  put  on  the  appearance  of  leather.  This 
usually  occupies  ten  days  in  a  weak  liquor,,  when  the  sides 
are  taken  out,  drained  and  stiffened,  (by  being  hung  up  in 
the  loft).  They  are  then  split.  Usually  there  are  two  splits 
taken  off,  one  main  split,  and  one  junior  or  small  one,  which 
covers  the  kidneys,  but  which  does  little  more  than  flatten 
the  side.  If  these  freshly  split  parts  are  thrown  back  into  a 
strong  liquor,  or  even  one  of  moderate  strength,  without 
wheeling  or  brushing,  they  will  become  "crusted"  over, 
and  will  not  take  the  tan  ;  but  if  thrown  into  the  wheel  for 
a  few  moments,  and  run  in  a  weak  sour  liquor,  then  all  dif- 
ficulty on  this  score  is  avoided.  The  old  method  of  brush- 


THE  LEATHER   MANUFACTURE.  215 

•&"</  with  a  stiff  brush  is  now  considered  too  expensive,  par- 
ticularly as  the  wheel  answers  the  purpose.  After  this 
wheeling  the  grain  portion  is  hung  in  the  vat  and  the  split 
portion  is  laid  away  with  bark. 

Seventh. — The  liquor  in  the  vats  is  changed,  but  not  the 
sides.  Some  run  off,  say  one-quarter  or  one-third  of  the 
liquor  into  the  junk,  and  pump  back  on  the  newer  packs,  re- 
plenishing the  bead  packs  with  new  liquor  from  the  leaches, 
while  others  press  round  their  yards  on  the  same  principle 
that  the  press  leaches  are  run.  In  either  case  great  care  is 
taken  to  feed  the  leather  both  slowly  and  uniformly,  so  that 
the  grain  is  kept  soft  and  full  without  "  drawing."  The 
effect  of  this  method  is  to  give  to  the  grain  portion  of  the  hide 
the  same  amount  of  tanning  that  would  be  given  to  a  whole 
skin,  i.  e.,  it  is  tanned  from  both  sides,  leaving  in  the  center 
mi  imaginary  line  of  partially  tanned  or  only  colored  fiber. 
This  imparts  a  toughness  that  distinguishes  the  leather  from 
ordinary  grain  leather  made  from  fully  tanned  hides.  By 
reason  of  the  thinness  of  the  grain  portion  very  weak  liquors 
can  be  used,  and  yet  the  tanning  is  completed  in  thirty  or 
forty  daj^s.  It  may  seem  anomalous,  but  it  is  nevertheless 
true,  that  tanning  makes  the  fiber  of  hides  comparatively 
tender,  or  less  tough,  and,  beyond  tanning  sufficiently  to  pre- 
serve the  gelatine,  the  further  filling  of  the  fiber  for  upper 
leather  should  be  avoided.  The  weak  liquor  process,  then, 
which  these  grain  leather  manufacturers  are  enabled  to  pur- 
sue, is  well  calculated  to  make  a  tough  fiber. 

Eighth.-^- Another  advantageous  result  of  splitting  the  hides 
intended  for  grain  leather  while  green  is  that  we  get  rid  of 
the  less  elastic  fiber  of  the  flesh,  including  the  nerve,  and  the 
grain  will  stretch  until  it  comes  to  its  proper  bearings.  This 
nautical  expression  conveys  the  idea  perfectly.  The  fiber 
must  be  distended  before  it  goes  into  the  shoe,  and  it  is  better 


216  THE  LEATHER  MANUFACTURE. 

to  let  it  distend  itself  while  green  than  to  tan  it  and  stretch 
i*  afterward.  This  point  may  seem  obscure  and  even  doubt- 
ful, but  the  writer  is  satisfied  that  there  is  much  in  it.  To 
illustrate — Why  is  it  that  damp  or  wet  leather  is  much 
tougher — will  bear  greater  strain — than  that  which  is  dry? 
Simply  because  all  the  fiber  pulls  evenly  when  wet,  but  when 
dry  there  is  not  the  same  uniformity.  For  the  same  reason, 
a  side  of  rough  leather  is  less  tough  than  the  same  side  after 
being  scoured  and  set  out,  and  when  grease  is  added  still 
greater  strength  of  fiber  is  secured.  It  is  found  that,  in  the 
manufacture  of  wire  rope,  greater  strength  is  secured  by  lay- 
ing the  wires  side  by  side  in  a  bundle,  rather  than  by  twisting 
them  up  as  in  a  rope.  Now  it  may  be  assumed  that  the  more 
equally  and  perfectly  the  fiber  of  the  hide  can  be  distended 
the  greater  will  be  the  aggregate  strength.  Whatever  may 
be  the  rationale  of  this  subject,  the  fact  stands  conceded  that 
grain  leather  manufactured  in  the  way  indicated  is  much 
touglier  than  when  made  in  the  old  way. 

The  scouring,  stuffing,  blacking  and  embossing,  is  con- 
ducted much  in  the  same  way  as  by  the  old  method.  Each 
of  these  processes  are  greatly  facilitated,  however,  by  having 
a  uniform  substance  and  tannage  to  treat.  The  bloom  and 
extractive  matter,  for  instance,  can  be  washed  out  of  these 
grain  sides  in  the  wheel  so  completely  that  they  require  little 
more  than  smoothing  off  before  hanging  them  up  to  partially 
dry  before  stuffing. 

In  all  trades  a  better  result  is  obtained  when  a  proper 
division  of  labor  is  observed,  and  this  is  notably  true  in  the 
manufacture  of  this  description  of  leather.  We  have  now 
several  large  manufactories  devoted  exclusively  to  the  pro- 
duction of  grain  and  buff  leather.  They  keep  in  mind  the 
result  they  wish  to  produce  from  the  beginning,  and  only 
buy  such  hides  as  will  suit  their  purpose.  This  regard  to 


THE   LEATHER  MANUFACTURE.  217 

true  economy  is  not  new  in  Great  Britain  or  France,  but  is 
here,  although  the  indications  are  not  few  that  our  tanners 
are  waking  up  to  a  better  conception  of  the  true  economies 
of  their  profession.  With  this  changing  condition  of  the 
trade,  it  may  be  possible  that  the  morocco  and  calfskin  tan- 
ners of  our  country  have  greater  occasion  to  fear  competition 
from  our  home  "  pebble  grain  "  manufacturers  than  from 
foreign  importations  of  their  own  goods. 


CHAPTEK   XXIV. 
CUEEYING  AND  FINISHING. 

THE  STUFFING  WHEEL  AND  HOW  TO  USE  IT TO  PURIFY  AND  CLEANSE  DIRTY 

GREASE HOW    TO    MAKE    STUFFING — FLESH    BLACKING FLOUR    AND 

SIZE  PASTES HARM  THAT  MAY  BE  DONE  BY  DEPENDENCE  UPON  RECIPES 

DAMPENING  LEATHER  BEFORE  AND  AFTER  APPLYING  OIL  AND  TALLOW. 

Iii  a  conversation  with  Mr.  CHARLES  KOEN,  (than  whom  no 
man  in  America  is  better  informed  on  the  philosophy  and 
practical  methods  of  dressing  and  tanning  leather),  the  writer 
asked  him  to  commit  to  writing  his  views  on  the  general  sub- 
ject of  his  profession.  He  said:  "Impossible!  It  would 
only  mislead;  no  man  can  know  how  to  finish  leather  from 
any  written  statement,  however  clearly  expressed."  To  the 
request  to  write  out  for  publication  his  methods  of  making 
oil  and  soap  blacking  ;  also  his  methods  of  compounding  >ize 
and  paste,  clearing  oil  that  is  impure,  etc.,  his  general  answer 
was  that  it  was  not  practicable.  Nothing  short  of  practical 
experience,  adapting  each  mixture  to  the  particular  kind  of 
leather  had  in  hand,  would  ever  make  a  successful  and  work- 
manlike job.  And  he  was  right.  As  well  might  a  landscape 
or  portrait  painter  attempt  to  give  directions  how  to  paint, 
as  for  a  currier  to  attempt  to  give  written  instructions  how- 
to  finish  leather. 

There  was  one  subject  that  Mr.  Korn  did  discuss  with 
considerable  warmth.  Several  efforts  having  been  made  to 
patent  the  stuffing  wheel,  which  he  introduced  and  gave  to 
the  trade,  without  claiming  a  patent,  he  said  that  all  attempts 
to  heat  up  the  air,  or  the  oil  and  tallow,  by  inserting  coils  of 


THE  LEATHER  MANUFACTURE.  219 

steam  pipe  inside  of  the  wheel,  or  by  introducing  heaj;  arti- 
ficially in  any  way,  were  useless.  His  method  of  mixing  his 
oil  and  tallow  had  been  uniform  and  always  successful.  The 
oil  and  tallow  should  be  heated  separately  and  mixed,  before 
putting  into  the  wheel,  in  such  proportions  as  the  nature  of 
the  leather  and  the  season  of  the  year  require ;  in  the  win- 
ter months  less  tallow  and  more  oil ;  in  the  warm,  summer 
months,  more  tallow  and  less  oil — both  seasons  varying  from 
an  equal  quantity  of  each,  according  to  the  circumstances. 
It  is  desirable  to  get  as  much  tallow  in  the  leather  as  possi- 
ble, without  making  it  hard  or  causing  it  to  "  spew."  If  the 
oil  and  tallow  congeal  and  attach  to  the  sides  and  corners 
of  the  wheel,  as  is  often  the  case,  a  jet  of  steam  from  a  pipe 
applied  to  the  inside  of  the  wheel  for  a  few  minutes  will  so 
soften  it  as  to  make  it  limpid,  when  it  will  unite  with  the 
fresh  oil  and  tallow.  When  once  the  wheel  is  in  motion,  the 
friction  occasioned  by  the  rubbing  of  the  sides  or  skins 
against  each  other  will  produce  heat  enough  to  keep  the  oil 
and  tallow  from  congealing,  particularly  if  the  atmosphere  is 
moderately  warm  in  the  shop,  as  it  should  be  always. 

It  is  a  remarkable  fact  that,  long  after  this  wheel  was 
introduced  into  public  use  here,  a  Scotchman  visiting  his 
native  country,  and  seeing  that  his  people  had  not  heard  of 
this  improvement,  actually  sold  the  exclusive  right  to  use  the 
machine  to  a  very  large  and  enterprising  manufacturing  firm 
in  Leeds.  With  the  free  intercourse  between  the  leather 
trades  of  Great  Britain  and  the  United  States  at  this  time 
it  would  hardly  be  possible  to  repeat  that  operation. 

The  slicker  whitener,  which  has  now  come  into  almost  uni- 
versal use,  is  to  be  superseded,  as  many  think,  for  all  work 
except  calfskins,  by  one  of  the  three  newly  patented  whiten- 
ing machines  noticed  in  subsequent  pages. 

The  purifying  and  cleansing  of  dirty  grease  before  it  is 


220  THE  LEATHER  MANUFACTURE. 

put  on  the  leather  is  accomplished  by  applying  heat.  Usu- 
ally, the  sun  on  a  warm  day  will  clarify  oil  that  is  exposed  to 
its  rays.  But  the  more  speedy  and  effective  way  is  to  place 
the  dirty  grease  in  a  barrel,  and,  for  every  thirty  gallons, 
apply  about  one  quart  of  sulphuric  acid ;  stir  it  very  thor- 
oughly, and  afterward  steam  the  oil  until  the  whole  fairly 
boils.  The  condensed  water  from  the  steam,  aided  by  the 
acid,  will  disengage  all  or  most  of  the  impurities  of  the  oil, 
and  carry  them  to  the  bottom,  when  the  whole  is  allowed  to 
stand  and  settle.  The  dirt  may  be  drawn  by  a  faucet  from 
the  bottom,  or  the  oil  may  be  carefully  dipped  off  from  the 
top.  In  this  way  the  writer  has  seen  railroad  grease,  as 
black  as  ink,  so  purified  as  to  make  very  serviceable  oil. 
This  railroad  oil  is  obtained  from  the  cotton  waste  used  in 
the  boxes  of  the  axles,  and  is  probably  the  most  unsightly 
oil  offered  the  currier,  and  yet  it  can  be  made  serviceable  in 
the  way  indicated,  both  as  to  cleanliness  and  color.  If  the 
acid  should  prove  objectionable  then  pulverized  chalk,  stirred 
in  the  oil  and  allowed  to  settle,  will  carry  down  and  off  its 
objectionable  features.  The  currier  will  seldom  have  oil  as 
bad  as  this  to  handle ;  generally  he  has  only  the  common 
"head  fats"  and  scrapings  from  the  tables,  which  will  yield 
to  the  treatment  above  indicated  most  readily. 

A  small  tank  or  hogshead  may  be  kept  standing  in  a  con- 
venient place,  with  one  head  out,  and  fitted  with  steam  coil 
in  the  bottom  ;  it  should  have,  also,  two  or  three  faucets  at 
short  distances  apart,  near  the  bottom,  from  which  all  impu- 
rities may  be  drawn  ;  this  apparatus  will  prove  a  most  use- 
ful one  in  the  purification  of  all  greases.  If  steam  is  not 
condensed  in  the  oil,  but  the  heating  is  done  by  a  close  coil, 
then  water  should  be  freely  poured  in  with  the  oil,  and  all 
boiled  together. 

The  making  of  stuffing  with  ordinary  oil  and  tallow  is  well 


THE   LEATHER  MANUFACTURE.  221 

understood,  but  of  the  use  of  degras  or  sod  oil  in  connection 
with  oil  and  tallow  less  is  generally  known.  Mr.  Korn  fur- 
nishes the  following  suggestions  :  Melt  the  tallow,  and  let 
it  stand  until  it  is  partially  cool.  If,  however,  degras  or  sod 
oil  be  mixed  with  the  tallow,  it  must  be  stirred  in  while  the 
tallow  is  hot ;  the  oil  added  may  be  put  in  while  the  tallow  is 
cooling.  A  little  water  with  the  sod  oil  and  degras  will 
lighten  the  color  very  much,  but  the  oil  must  be  added  after, 
never  before  the  degras. 

Flesh  blacking  is  made  either  with  lampblack  and  soap  or 
lampblack  and  oil ;  if  "  soap  blacking  "  is  used,  oil  is  freely 
applied  afterwards  to  fasten  the  color  and  body  of  the  black. 
The  principle  advantage  claimed  for  soap  blacking  is  that  it 
fills  the  flesh  with  a  better  body  and  covers  defects  which 
show  through  if  oil  and  lampblack  alone  are  used.  The  dis- 
advantages are  that  when  this  leather  is  crimped  for  boots, 
the  blacking  washes  off  and  leaves  a  coarse  surface,  while  the 
alkali  in  the  soap  will,  if  allowed  to  lie  for  a  long  time,  more 
or  less  destroy  the  grease  and  impart  a  harsh  feeling  to  the 
leather ;  pure  oil  blacking  will  grow  softer  by  age.  So  far 
as  known  to  the  writer  soap  blackicg  is  now  used  in  no  other 
country,  and  is  at  present  used  here  only  in  the  modified 
form  to  which  attention  has  been  called. 

Flour  paste  is  used  first  after  the  soap  blacking.  It  is  made 
of  flour,  with  soap  added — say  to  every  pail  of  flour  use  two 
pounds  of  hard  brown  soap,  which  is  to  be  boiled  with  the 
paste.  Some  add  tallow  also — for  every  pail  of  flour  paste 
using  a  piece  as  large  as  an  egg. 

Size  paste  is  made  as  follows :  Dissolve  four  ounces  of 
glue  in  warm  water  ;  add  a  small  piece  of  tallow,  say  half  an 
ounce ;  dilute  in  water  until  the  proper  consistency  is  ob- 
tained to  spread  easily  with  a  sponge. 

The  writer  refrains  from  giving  further  suggestions  on  these 


222  THE   LEATHER  MANUFACTURE. 

topics  lest  he  should  subject  himself  to  the  criticism  with 
which  Mr.  Korn  closed  his  observations  :  u  Writers  of  books 
and  lecturers  are  mere  theorists,  and  are  seldom  good  work- 
men." A  small  treatise  on  Tacning  and  Currying,  by  "  a 
Maryland  tanner  and  currier,"  in  addition  to  other  leading 
suggestions,  contains  "  twenty-five  valuable  recipes,"  on  which 
hang  most  of  the  principles  involved  in  the  tanning  and  fin- 
ishing of  leather.  Should  the  writer  attempt  to  imitate  his 
example,  and  lay  down  the  absolute  rules  of  action  govern- 
ing all  cases,  giving  recipes  in  a  dogmatic  way,  it  would 
probably  do  more  harm  than  good.  For  instance  urine, 
until  within  the  past  twenty  years,  has  been  the  only  known 
solution  to  kill  the  grease  preparatory  to  the  blacking  of  the 
grain  of  leather,  and  all  recipes  were  based  on  this  chemical 
agent.  Now,  the  chemist  who  suggested  that  any  other 
alkali  would  do  this  service  just  as  well  and  a  great  deal 
more  uniformly  saved  the  currier  one  of  his  greatest  nui- 
sances, and  insured  a  much  improved  result.  At  present  the 
use  of  soda  ash  or  sal  soda  takes  the  place  of  the  "  sig." 
barrel.  The  recipes  above  mentioned  are  full  of  antiquated 
notions  of  this  kind,  which  it  will  be  well  to  forget  as  soon 
as  possible.  What  we  want  to  know  is  the  chemical  charac- 
teristics of  all  the  agents  we  employ.  Then  we  shall  know 
how  to  substitute  the  one  for  the  other,  and  learn  to  employ 
those  that  are  the  most  economical  as  well  as  serviceable. 

In  closing  this  chapter  the  writer  would  call  attention  to  a 
new  and,  to  some  extent,  revolutionary  idea  in  regard  to  the 
stuffing  of  leather.  It  has  always  been  held  indespensable 
that  leather  should  be  partially  wet  or  dampened  before  the 
oil  and  tallow  was  allowed  to  enter  the  fiber.  If  applied 
when  too  wet  the  oil  would  not  enter,  and  if  too  dry  the  fiber 
would  be  "  burned  ; "  this  has  always  been  the  popular  idea. 
No  miner  would  think  of  oiling  his  old  boots,  no  farmer  his 


THE  LEATHEE  MANUFACTURE.  223 

old  harness,  no  mill  owner  his  old  belt,  without  soaking  in 
water  and  preparing  the  leather  to  receive  the  grease.  It  is 
the  opinion  of  the  writer  that  no  greater  fallacy  ever  pre- 
vailed. Worn  out  leather— that  is,  leather  that  has  lost  its 
vitality  by  the  evaporation  of  its  grease,  should  be  replen- 
ished by  having  grease  applied  to  it  while  in  a  dry  state,  and 
after  the  oil  or  grease  has  entered  and  been  absorbed  by  the 
thirsty  pores,  then  should  follow  warm  water  to  modify  and 
control  the  action  of  the  oil.  It  will  be  seen  at  once  that  the 
oil  has  taken  its  place  in  the  center  of  the  leather,  while  the 
water  is  on  the  outside  and  may  be  evaporated  easily  ;  but 
if  the  water  is  inside  it  has  to  pass  the  oil,  and  there  must 
be  delay.  If  the  oil  is  lodged  in  the  center  it  must  work 
toward  the  surface  very  slowly,  and  when  evaporated,  which 
will  require  months  and  even  years,  then  it  must  be  replen- 
ished in  the  same  way. 

It  may  be  asked  why  soak  with  warm  water  at  all,  on  this 
theory  ?  Why  not  soak  with  oil  and  tallow  exclusively  ?  The 
answer  is  because  the  oil,  under  such  circumstances,  will 
"  slough  "  off,  but  if  water  not  exceeding  110  degrees  in  heat 
be  applied  it  will  drive  in  the  oil  from  the  surface  and  modify 
that  greasy  feeling  and  untidy  appearance  which  attaches  to 
over  stuffed  leather.  Over  stuffed  leather  can  also  be  cured 
of  its  defects  by  being  immersed  in  hot  water  to  the  extent 
above  indicated.  If  no  thermometer  is  at  hand  to  test  the 
degree  of  heat  it  will  be  safe  to  immerse  the  over  stuffed 
leather  for  one  minute  in  water  as  warm  as  the  human  hand 
and  pulse  can  bear,  and  the  result  will  be  that  all  the  excess 
of  grease  will  be  driven  to  the  center,  and  the  surface  will 
dry  fair.  That  no  oil  has  passed  out  of  the  side  will  be 
demonstrated  by  the  fact  that  no  grease  will  appear  on  the 
surface  of  the  water.  It  must  then  have  gone  in,  which  will 
be  shown  by  the  retained  weight. 


CHAPTEE    XXV. 

DIRECTIONS  FOE  THE  CONSTEUCTION  OF  DETACHED 
FUENACES  FOE  BUENING  WET  SPENT  TAN. 


BY  THEEON   SKEEL,   C.   E. 


The  problem  in  designing  a  furnace  and  boilers  for  burning 
wet  spent  tan  to  furnish  steam  for  a  tannery  is  different  from 
that  in  designing  a  furnace  for  coal  or  wood  in  that  the  fuel 
has  generally  no  value  for  any  other  purpose,  all  that  is  not 
burned  being  thrown  away.  In  case  the  tannery  is  not 
located  where  the  spent  tan  can  be  run  off  through  the 
bottom  of  the  leach  by  a  stream  of  water,  but  where  it  has 
to  be  shoveled  from  the  leach  and  carted  away,  tanners 
will  find  it  cheaper  (so  far  as  first  cost)  to  burn  all  the  tan 
they  leach,  for  by  so  doing  the  boilers  may  be  made  smaller 
than  would  be  necessary  if  they  burned  as  little  tan  as  they 
could  get  along  with,  but  as  the  heat  is  more  intense  they 
will  burn  out  sooner.  A  sole  leather  tannery  can  be  run  by 
burning  about  one-half  the  tan  leached,  if  the  ovens  and 
boilers  are  well  proportioned,  while  an  upper  leather  tannery 
will  need  to  burn  nearly  all  the  tan  leached,  even  in  the  best 
form  of  furnaces  and  boilers ;  or,  if  the  furnaces  and  boilers 
are  of  inferior  design,  will  run  short  of  bark  at  certain  seasons 
of  the  year. 

A  tannery  producing  annually  20,000  sides  of  sole  leather 


THE  LEATHER  MANUFACTURE.  225 

will  need  for  tanning  about  2,000  cords  of  hemlock  bark, 
measured  before  being  ground,  and  must  burn  one-half  of 
this,  or  1,000  cords,  to  make  all  the  steam  used  in  the  tannery 
to  run  engines  and  pumps,  heat  liquor,  etc.  The  weight  of 
an  average  cord  of  air-dried  hemlock  bark,  as  measured  in 
the  pile  before  being  ground,  will  be  2,000  pounds.  In  the 
process  of  leaching  this  cord  of  bark  will  lose  nearly  400 
pounds,  and  the  portion  remaining  will  weigh  1,600  pounds 
in  the  same  state  of  dryness  as  before  being  leached,  but  as 
it  comes  from  the  leaches  will  bring  with  it  in  addition  2,000 
pounds  of  water,  making  the  weight  of  the  wet  spent  tan  re- 
sulting from  one  cord  of  chip  bark  3,600  pounds.  The  total 
weight  of  spent  tan,  therefore,  produced  each  year  by  a 
20,000  -side  sole  leather  tannery  will  be  (3,600X2,000—) 
7,200,000  pounds,  and  the  weight  of  the  portion  that  must 
be  burned,  being  about  one-half  —  3,600,OCO  pounds. 

If  the  machinery  of  the  tannery  runs  twelve  hours  a  day 
nnd  ^00  days  in  the  year,  the  total  number  of  hours  will  be 
(300X12=-)  3,600,  and  therefore  the  weight  of  wet  spent  tan 
that  must  be  burned  each  hour  in  a  furnace  and  boilers  of  the 
best  construction  and  design  (3,600,000-^,600=)  1,000,  or  a 
thousand  pounds  an  hour. 

Table  I  is  computed  in  this  way» 

TABLE  I.  —  WEIGHT  OF  WET  SPENT  TAN  THAT,  MUST  BE  BURNED  EACH  HOUR 

IN  A  FURNACE  AND  BOILER  OF  BEST-  CONSTRUCTION:  TO  FURNISH  ALL 
THE  STEAM  NECESSARY  FOR  THE  TANNERY,  IF  THE  MACHINERY  RUNS 
12  HOURS  A  DAY  AND  300,  DAYS  A  YEAR. 


Number  oi'  Side^  Pounds,  of  Wet  Spent  Tan 

Tanned  Annually.  Burned  Each  Hour. 

10,000.  ......  ......  ........  ,",  ...  500 

20,000.........  .....  ............  1,000 

50,000  .................  ,_  .....  2,500 

80,000......  .....  .........  .......  4,000; 

100,000  .................  ...  ........  5,OQQ; 


15 


226  THE  LEATHER  MANUFACTURE. 

Having  determined  how  much  tan  must  be  burned,  the  next 
consideration  is  whether  the  oven  shall  be  fed  from  the  top 
or  from  the  front.  Except  under  very  exceptional  circum- 
stances I  consider  it  is  better  to  feed  from  the  top.  If  the 
oven  is  fed  from  the  front  one  man  cannot  feed  fast  enough 
to  keep  up  steam  in  a  larger  tannery  than  60,000  sides,  even 
if  the  tan  is  brought  into  the  fire  room  floor  by  a  laborer, 
(if  he  has  to  attend  to  the  water  in  the  boiler  at  the  same 
time,)  while,  if  the  oven  is  fed  from  the  top,  one  man  can 
supply  bark  fast  enough  to  keep  up  steam  in  a  200,000-side 
tannery.  An  oven  fed  from  the  top  does  not  need  nearly 
such  close  attention  as  an  oven  fed  from  the  front.  The 
former  may  be  filled  up  and  not  touched  again  for  an  hour, 
if  the  fireman's  attention  is  withdrawn,  as  often  happens 
when  the  pump  breaks  down  or  in  other  cases,  while  the 
oven  fed  from  the  front  must  be  supplied  with  bark  every 
fifteen  minutes.  An  oven  fed  from  the  top  may  be  smaller 
than  is  admissible  in  an  oven  fed  from  the  front,  and  requires 
less  skill  in  firing.  The  only  case  when  it  would  se'  in  desira- 
ble to  use  an  oven  fed  from  the  front  is  when  it  is  very  incon- 
venient to  get  the  bark  up  on  top  of  the  oven,  or  when  there  is 
a  .small  hight  over  the  oven,  as  when  the  floor  of  the  room 
above  is  so  near  the  top  of  the  oven  as  to  be  in  danger  from 
fire. 

In  orrler  to  successfully  burn  wet  tan  it  is  necessary  that 
the  surface  of  heated  brick  work  surrounding  the  tan  in  the 
furnace  should  be  large  in  proportion  to  the  weight  of  tan 
1  >urned,  in  order  that  this  surface  should  not  be  cooled  off  by 
the  water  evaporated  from  the  fresh  charge  of  wet  tan,  below 
the  temperature  necessary  to  ignite  the  gases  given  off  by 
that  tan  after  it  is  dried  and  before  it  commences  to  burn. 
This  condition  requires  a  large  oven  and  a  slow  rate  of  com- 
bustion. It  is  found  in  prac4ice  that  the  combustion  is  sen- 


THE   LEATHER   MANUFACTURE.  227 

sibly  perfect  when  the  wet  spent  tan  is  burned  at  the  rate  of 
15  pounds  on  each  square  foot  of  grate  surface  per  hour. 

Table  II  is  calculated  from  Table  I  in  this  way,  and  gives 
the  necessary  grate  surface  for  a  furnace  fed  from  the  top. 

TABLE  H. — AEEA  OF  GRATE  SUEFACE  NECESSARY  IN  A  TANNERY  BURN- 
ING ONE-HALF  THE  TAN  LEACHED  IN  AN  OVEN  FED  FROM  THE  TOP 
TO  FURNISH  ALL  THE  STEAM  NEEDED,  THE  MACHINERY  RUNNING  12 
HOURS  A  DAY  AND  300  DAYS  IN  THE  YEAR. 

Number  of  Sides  Area  of  Grate 

Tanned  Annually.  in  Square  Feet. 

10,000 33 

20,000 66 

50,000 166 

80,000... 266 

100,000 333 

This  amount  of  grate  surface  may  be  obtained  in  several 
ovens  if  necessary.  The  ovens  had  better  be  at  least  6  feet 
wide,  and  as  long  as  convenient.  The  feed  holes  should  be 
two-thirds  of  the  width  of  the  oven  between  centers,  that  is, 
for  an  oven  6  feet  wide  the  feed  hole  should  be  4  feet  between 
centers.  The  feed  holes  may  be  12  to  18  inches  in  diameter 
at  the  top,  and  larger  at  the  bottom,  as  the  bark  is  fed  in 
more  easily  through  a  large  hole  than  a  small  one.  The 
hight  of  the  oven,  measured  from  the  grate  bars  to  the  crown, 
should  be  three-quarters  of  its  width,  that  is,  an  oven  6  feet 
wide  should  be  4J  feet  high  from  the  crown  to  the  grate. 

In  order  to  take  up  sufficient  heat  the  heating  surface  in 
the  boilers  should  be  one-half  of  one  square  foot  for  each 
pound  of  wet  spent  tan  burned  per  hour  in  an  oven  fed  from 
the  top.  This  amount  of  heating  surface  will  reduce  the 
temperature  of  the  gas  in  the  chimney  to  about  600°.  Table 
III  is  computed  from  this  proportion.  [The  heating  surface 
is  all  the  surface  of  the  boiler,  whether  on  the  shell  or  in  the 
flues  or  tubes,  that  has  water  on  one  side  and  the  hot  gas  on 
the  other.] 


228  THE   LEATHER   MANUFACTURE. 

TABLE  ILL — AREA  OF    HEATING    SURFACE  NECESSARY    FOR  A  TANNERY 

HAVING  AN  OVEN  FED  FROM  THE  TOP,  AND  BURNING  ONE-HALF  OF 
THE  TAN  LEACHED  TO  MAKE  ALL  STEAM  USED,  IF  THE  MACHINERY 
RUNS  12  HOURS  A  DAY  AND  300  DAYS  IN  THE  YEAR. 

Number  of  Sides  Area  of  Heating  Sur- 

Tanned  Annually.  face  in  Square  Feet. 

10,000 250 

20,000 500 

50,000 1,250 

80,000 2,000 

100,000 2,500 

In  case  an  oven  fed  from  the  front  is  used,  the  heating 
/surface  must  be  20  per  cent,  more — that  is,  for  a  10,000-side 
tannery,  300  square  feet,  etc. 

In  order  to  burn  the  wet  spent  tan  at  the  rate  given  the 
chimney  must  be  at  least  70  feet  high  and  must  have  an  area 
of  at  least  one-quarter  of  one  square  inch  for  each  pound  of 
wet  spent  tan  burned  per  hour,  but  the  performance  will  be 
more  satisfactory  if  the  chimney  is  made  100  feet  high,  and 
of  an  area  of  one-half  of  one  square  inch  for  each  pound  of 
wet  spent  tan  burned  per  hour.  The  caller  chimney  will  give 
a  better  draft,  which  will  get  up  steam  quicker  after  it  has 
been  allowed  to  run  down,  while  the  larger  area  will  give  a 
slower  current  in  the  chimney,  and  the  sparks  will  not  be  so 
likely  to  be  carried  from  the  chimney  and  to  endanger  the 
agjacent  buildings.  The  chimney  may  be  made  of  sheet 
iron,  but  brick  is  recommended  as  a  better  material,  or  sheet 
iron  lined  with  brick.  The  iron,  if  not  lined  with  brick,  in 
time  rusts  out,  and  cold  air  leaks  in  and  spoils  the  draft. 
The  brick  when  once  built  is  permanent.  A  larger  chimney 
than  given  in  the  following  table  (calculated  at  the  rate  of 
one-half  of  one  square  inch  to  each  pound  of  wet  spent  tan 
burned  per  hour)  is  an  advantage. 


THE  LEATHER  MANUFACTURE.  229 

TABLE  IV. — DIMENSION  OF  CHIMNEY  NECESSARY  TO  CONSUME  ONE-HALF 

OF  TAN  LEACHED  WITHOUT  ENDANGERING  SURROUNDING  BUILDINGS  BY 
SPARKS  CARRIED  UP  BY  CURRENT  OF  GAS  WHEN  MACHINERY  RUNS  DUR- 
ING 12  HOURS  A  DAY  FOR  300  DAYS  IN  THE  YEAR. 

Diameter  of  Chim-    Sides  of  Chimney, 

Number  of  Sides        Area  in  Square  ney,  if  it  is  Circu-        if  it  is  square, 

Tanned  Annually.  Inches.  lar,  in  Inches.  in  Inches. 

10,000  250  18  16 

20,000  500  25  23 

50,000  1,250  40  36 

80,000  2,000  50  45 

100,000  2,500  56  50 

The  size  of  the  chimney  may  be  the  same  whether  the 
oven  is  fed  from  the  top  or  from  the  front.  There  must  be 
a  damper  in  the  chimney,  or  what  is  better,  a  damper  be- 
tween the  outlet  of  each  nest  of  boilers  and  the  chimney,  to 
regulate  the  draught. 

The  cross  section  of  the  flues  or  tubes  in  the  boiler  must 
be  (in  the  case  of  an  oven  fed  from  the  top)  as'  great  as  the 
necessary  area  of  chimney,  or  one-quarter  of  a  square  inch 
for  each  pound  of  wet  spent  tan  burned  per  hour,  for  the  gas 
is  hotter  and  more  bulky  when  it  enters  the  flues  than  when 
it  enters  the  chimney.  Only  one  pound  of  wet  spent  tan  can 
be  burned  for  each  one-quarter  square  inch  of  area  of  the 
flues  or  tubes  in  an  oven  fed  from  the  front,  but  the  flues  or 
tubes  may  be  made  larger  than  this,  and  the  draft  checked 
by  the  dampers  or  ash-pit  doors.  Thus,  if  a  tanner  has  an 
oven  fed  from  the  front  and  two  horizontal  flue  boilers  with 
two  twelve-inch  flues  each,  the  total  cross  section  is  452 
square  inches,  and  the  greatest  weight  of  wet  spent  tan  that 
can  be  burned  per  hour  is  (452-hJ=)  1,808.  But  in  order  to 
get  perfect  combustion  the  flues  should  be  twice  as  large  as 
this,  or  one-half  square  inch  area  for  each  pound  of  wet  spent 
tan  burned  per  hour.  It  is  of  no  advantage  to  have  the  flues 
or  tubes  of  larger  area  than  one-half  of  one  square  inch  for 


230  THE  LEATHEK  MANUFACTURE. 

each  pound  of  wet  spent  tan  burned  per  hour,  (as  given  in 
table  V,)  and  all  tubes  or  flues  added  after  that  area  is 
reached  are  entirely  useless.  The  flues  or  tubes  in  an  oven 
fed  from  the  top  may  be  made  of  any  area  from  one-quarter 
to  one-half  of  one  square  inch  for  each  pound  of  wet  spent 
tan  burned  per  hour,  and  if  the  length  of  the  boilers  is  pro- 
portioned to  the  area  of  the  tubes  so  that  the  heating  surface 
is  the  same  in  each  case  the  effect  will  be  the  same,  but  short 
boilers  with  large  tubes  or  flues  are  cheaper  to  build  than 
longer  ones  with  smaller  flues  or  tubes. 

TABLE  V. — AREA  OF  FLUES  OR  TUBES  THAT  is  OF  ADVANTAGE  IN  BURNING 

WET  SPENT  TAN  IN   ANY   KIND    OF   OVEN,  WHEN   THE   MACHINERY  RUNS 
12  HOURS  A  DAY  AND  300  DAYS  IN  THE  YEAR. 

Number  of  Sides  Area  of  Tubes  or 

Tanned  Annually.  Flues  in  Square  Inches. 

10,000 250 

20,000 500 

50,000 : 1,250 

80,000 2,000 

100,000  2,500 

Horizontal  tubular  boilers  are  the  cheapest,  and  if  the 
water  used  is  free  from  sediment  or  mineral  water — that  is, 
if  the  water  comes  from  a  clear  stream  of  soft  water — will 
last  from  eight  to  ten  years,  but  as  they  contain  but  little 
water  in  comparison  with  the  heating  surface,  must  be  fed 
often,  and  are  likely  to  leak  or  to  have  the  tubes  burned  out 
if  the  water  is  often  allowed  to  get  low  and  then  quickly 
pumped  up.  If  the  water  contains  much  sediment,  or  if  it  is 
"  hard,"  the  tubes  are  soon  covered  with  a  deposit  of  mud  or 
scale.  If  the  deposit  is  mud  the  boiler  can  be  washed  out, 
but  if  it  is  scale  from  "hard  water"  in  a  few  years  the  tubes 
are  coated  so  thick  that  they  have  to  be  taken  out  and  new 
ones  put  in. 

A  tubular  boiler  of  the  dimensions  given  in  the  tables  must 


THE   LEATHER   MANUFACTURE.  231 

be  fed  every  twenty  minutes  at  least,  and  will  occupy  the 
unremitting  attention  of  the  fireman  or  engineer. 

Plain  cylinder  boilers  are  the  most  expensive,  but  are  the 
easiest  kept  in  repair,  and  the  easiest  cleaned  from  mud  or 
scale.  They  have,  in  addition,  the  disadvantage  of  requiring 
a  larger  boiler  house  and  more  expensive  setting  and  founda- 
tions. They  contain  so  much  water  that  they  may  be 
neglected  for  several  hours  without  danger,  and  the  steam 
pressure  will  be  more  nearly  constant  than  with  horizontal 
tubular  or  flue  boilers. 

Horizontal  flue  boilers  are  more  expensive  than  the  tubular 
and  less  expensive  than  cylinder  boilers,  and  they  do  not 
require  so  large  a  boiler  house  or  so  expensive  a  setting  or 
foundation  as  the  cylinder  boilers,  while  they  can  be  cleaned 
and  repaired  with  more  facility  than  the  tubular  boilers. 
They  will  last  from  sixteen  to  twenty  years,  or  twice  as  long 
as  the  tubular.  They  contain  more  water  than  the  tubular 
boilers,  and  (at  the  rate  of  combustion  recommended  in  this 
paper)  may  be  safely  neglected  for  at  least  one  hour  without 
the  water  getting  too  low.  If  horizontal-flue  or  cylinder 
boilers  are  used,  they  may  be  connected  together  in  nests  of 
from  two  to  six  boilers,  and  each  nest  furnished  with  a  feed, 
blow,  safety  and  stop  valve. 

The  cost  of  the  boiler  alone  for  a  20,000-side  tannery 
wiU  be  in  1876  : 

1  horizontal  tubular  boiler,  54  inches  diameter,  12  feet 

long,  43  3 J-inch  tubes,  shell  |  inch,  at  lOc $700 

Or,  3  horizontal-flue  boilers,  40  inches  diameter,  16 
feet  long,  two  12-inch  flues,  each  shell  5-16-inch, 
at  7Jc $1,000 

Or,  4  cylinder  boilers,  30  inches  diameter,  36  feet  long, 

sheU  J  inch,  at.. $1,100 

From  this  it  appears  that  the  flue  and  cylinder  boilers  cost 


232  THE  LEATHEK  MANUFACTUBE. 

nearly  the  same,  but  the  flue  boilers  are  cheaper  to  set.  On 
the  whole,  flue  boilers  are  to  be  recommended  as  the  best 
unless  the  water  is  very  Jiard,  or  unless  it  is  particularly 
desirable  to  have  a  boiler  that  needs  very  little  attention. 

The  best  way  to  feed  the  boiler  is  by  a  pump  worked  from 
the  main  engine,  and  the  next  best  way  is  by  an  injector.  If 
the  boiler  is  fed  by  an  injector  the  heater  to  heat  the  feed 
water  by  the  exhaust  steam  cannot  be  used,  but  this  is  not 
of  importance,  as  the  saving  of  10  per  cent,  that  may  be 
made  by  the  heater  is  of  no  moment  when  the  fuel  has  no 
value,  and  the  cost  of  the  heater  may  be  transferred  to  the 
boilers.  If  the  boilers  are  fed  by  a  steam  or  other  pump  the 
heater  had  better  be  used,  as  cold  feed  water  has  an  inju- 
rious effect  on  the  boilers.  If  they  are  fed  by  a  punip  worked 
by  the  main  engine  it  is  well  to  arrange  the  pump  so  that  the 
stroke  may  be  varied,  and  to  adjust  it  to  work  all  the  time. 

In  case  the  tannery  is  not  located  where  the  spent  tan  can 
be  thrown  into  the  creek,  or  where  there  is  any  market  for 
it,  tanners  will  find  it  cheaper  to  burn  it  all  rather  than  cart 
any  away.  In  that  case  they  must  provide  larger  ovens,  and 
will  not  need  so  large  boilers  as  when  they  only  burn  one- 
half. 

The  wet  spent  tan  may  be  burned  in  this  wasteful  manner 
(the  object  being  to  get  rid  of  and  not  to  economize  it)  at 
the  rate  of  30  pounds  per  square  foot  of  grate  per  hour,  and 
the  ovens  need  to  be  made  one-third  larger  than  given  in 
table,  for  same  sized  tannery,  and  the  boilers  may  be  made 
one-third  shorter,  but  the  diameter  and  number  of  tubes  or 
flues  must  be  the  same,  or  the  diameter  had  better  be  one- 
eighth  more.  The  hight  and  diameter  of  chimney  may  be 
the  same.  That  is,  the  ovens  must  be  one-third  longer 
and  the  boilers  may  be  one-third  shorter,  if  the  tanner 
wishes  to  burn  all  the  tan  made,  than  if  he  burns  only  one- 


THE  LEATHER  MANUFACTURE.  233 

half.  In  this  way  the  boilers  are  less  expensive,  but  as  they 
will  wear  out  (owing  to  the  higher  temperature  of  the  gas 
under  them)  in  considerably  less  time,  this  arrangement  of 
small  boilers  and  large  ovens  is  not  to  be  recommended. 

As  an  example  in  the  application  of  the  foregoing  rules 
suppose  it  is  desired  to  design  a  furnace  to  be  fed  from  top, 
furnish  steam  for  a  tannery  tanning  100,000  sides  of  sole 
leather,  and  running  night  and  day.  This  would  be  equiva- 
lent to  a  50,000  side  tannery  running  12  hours  a  day,  and  we 
find  from  the  tables  as  follows : 

Grate  surface   square  feet.  166J 

Heating  surface square  feet.  1,250 

Cross  section  flues.        .  . .  square  inches.  1,250 

Diameter  of  chimney inches.  40 

Pounds  wet  spent  tan  per  hour 2,500 

The  grate  surface  may  be  put  in  two  ovens,  each  6  feet 
wide  and  14  feet  long,  with  three  feed  holes,  each  5  feet  be- 
tween centers,  or  may  be  put  in  one  oven  7  feet  wide  and  24 
feet  long,  with  four  feed  holes,  each  5  feet  between  centers. 
The  last  arrangement  would  be  the  cheaper,  but  the  first  is 
to  be  preferred,  because  it  is  well  to  have  a  pair  of  ovens, 
that  one  may  be  used  if  the  other  breaks  down. 

The  boiler  surface  may  be  obtained  in  two  horizontal 
tabular  boilers,  each  60  inches  diameter  and  12  feet  long, 
with  sixty  3J  inch  tubes,  or  in  four  horizontal  flue  boilers, 
each  42  inches  in  diameter  and  22  feet  long,  with  two  14 
inch  flues  each ;  or  eight  cylinder  boilers,  each  30  inches 
in  diameter  and  36  feet  long. 

The  chimney  would  be  40  inches  in  diameter,  or  36  inches 
square.  If  it  were  desired  to  have  an  oven  fed  from  the 
fro  at,  then  the  grate  surface  must  be  the  same,  and  the  heat- 
ing surface  25  per  cent,  more  on  1,600  square  feet. 

The  depth  of  the  grate  must  not  be  more  than  the  fireman 


23-1  THE   LEATHER   MANUFACTURr. 

can  easily  throw  the  tan,  or  from  6  to  7  feet,  and  therefore 
the  width  must  be  from  28  to  24  feet. 

The  grate  surface  could  be  obtained  in  two  ovens,  each  7 
feet  deep  and  12  feet  wide,  or  in  three  ovens,  each  6  feet  deep 
and  9  feet  wide. 

The  boilers  must  have  25  per  cent,  more  surface  than  for 
the  oven  fed  from  the  top,  so  that  the  same  boilers  as  were 
used  for  the  furnace  fed  from  the  top  will  answer  if  they  are 
made  one-quarter  longer,  viz. : 

Tubular  boilers 15  feet  long. 

Flue  boilers 28  feet  long. 

Cylinder  boilers , 45  feet  long. 

A  still  better  arrangement  would  be  six  horizontal  flue 
boilers,  40  inches  in  diameter  with  two  12-inch  flues,  22  feet 
long. 

In  case  the  oven  is  fed  from  the  front  I  consider  that  the 
grate  bars  had  better  be  from  one  foot  to  one  foot  and  a  half 
below  the  sill  of  the  doors  through  which  the  tan  is  fed,  as  it 
will  be  found  easier  to  throw  the  tan  to  the  back  of  the  grate 
when  they  are  so  placed  than  when  they  are  flush  with  the 
sill,  as  ordinarily  arranged,  and  also  for  the  same  reason  that 
they  should  be  from  six  inches  to  a  foot  lower  at  the  back 
than  at  the  front,  in  place  of  being  level  as  usual.  The  grate 
bars  are  placed  flush  with  the  door  sill  for  a  coal  fire  to  facil- 
itate cleaning  the  fire,  which  never  need  be  done  when  tan 
bark  is  burned. 

The  furnace  doors  should  be  made  with  a  register  to  be 
opened  as  the  fire  may  require. 

The  ash  pit  doors  should  have  registers,  and  the  draft 
should  be  regulated  by  partly  closing  the  registers  in  place 
of  the  damper. 

One  of  the  principal  reasons  why  tan  burning  ovens  often 
fail  to  give  satisfaction  is  that  the  joints  around  the  various 


THE  LEATHER   MANUFACTURE.  235 

openings  and  the  sheet  iron  works  are  poorly  made,  aijd  cold 
air  leaks  into  the  flues  or  chimney  and  chills  the  water  or  in- 
jures the  draft.  No  air  should  be  admit  fad  to  mix  with  the  gas 
after  it  has  left  the  furnace. 

The  space  between  the  bottom  of  the  grate  bars  and  the 
floor  of  the  ash  pit  should  be  at  least  two  feet,  and  may  be 
as  much  more  as  is  convenient  without  detriment. 

The  space  between  the  grate  bars  should  not  be  more  than 
|  inch,  and  may  be  as  little  as  J  inch.  With  this  width  of 
space  (J-  inch)  only  a  very  insensibly  small  portion  of  the  tan 
will  fall  through  into  the  ash  pit. 

It  has  been  customary  in  furnaces  fed  from  the  front  to  use 
the  cone  grate  bars.  I  do  not  think  these  are  any  advantage, 
but  that  the  furnace  will  work  just  as  well  with  the  ordinary 
bars,  which  are  cheaper. 

The  grate  bars,  whether  for  an  oven  fed  from  the  top  or 
front,  may  be  made  much  lighter  than  for  a  coal  fire,  as  they 
have  only  to  carry  a  load  of  about  30  pounds  to  the  square 
foot  in  place  of  60  pounds  as  in  a  coal  fire,  and  are  not  broken 
by  blows  of  the  slide  bar  and  hoe  in  cleaning  fire.  The  heat 
they  are  called  on  to  endure  is  only  about  two-thirds  of  a 
coal  fire,  and  they  may  be  safely  made  as  light  as  60  pounds 
per  square  foot  when  31  inches  long.  When  the  tannery  is 
so  situated  that  it  is  convenient  to  burn  all  the  tan  the  ovens 
may  be  made  one-third  larger  and  the  boilers  with  one-third 
less  heating  surface.  The  chimney  should  also  be  one-third 
larger  cross  section,  in  order  to  avoid  danger  from  sparks. 
Under  these  circumstances  all  the  steam  necessary  will  be 
made  by  the  boilers,  but  all  the  tan  made  must  be  burned, 
and  the  gases  will  leave  the  boiler  at  nearly  a  red  heat,  or 
about  1,000°.  This  temperature  will  set  fire  to  wood,  and 
great  care  must  be  taken  to  keep  the  flue  leading  to  the 
chimney  out  of  contact  with  all  woodwork. 


236  THE  LEATHER  MANUFACTURE. 

Six  plates  illustrating  the  two  kinds  of  furnaces  described 
in  this  chapter  are  given  in  subsequent  pages.  The  first 
three  plates,  I,  II,  III,  are  plans  of  a  set  of  ovens  to  be  fed 
from  the  top,  which  are  located  at  Wilcox,  Pa.,  and  used  to 
supply  steam  to  the  tannery  at  that  place,  which  has  a 
capacity  of  one  hundred  thousand  hides  per  annum.  These 
ovens  and  boilers  are  placed  in  a  building  distant  three 
hundred  feet  from  the  nearest  of  the  other  buildings  of  the 
tannery. 

Plate  III,  figure  1,  shows  a  plan.  In  the  left-hand  portion 
of  the  figure  the  roof  of  the  building  is  supposed  to  have  been 
removed,  so  that  the  fire-room  floor  and  the  tops  of  the  boilers 
are  seen.  In  the  right-hand  portion  the  fire-room  floor  and 
the  boilers  are  also  supposed  to  have  been  removed,  so  that 
the  grate  bars  and  the  dividing  wall  under  the  boilers  are 
seen. 

Figures  2  and  3,  on  the  same  plate,  show  east  and  west 
elevations.  In  figure  2  the  rear  wall  of  the  right-hand  oven 
is  supposed  to  have  been  removed,  so  as  to  show  the  boilers 
and  the  dividing  wall  between.  In  figure  3  the  front  wall  is 
supposed  to  have  been  removed  so  as  to  show  the  arches  over 
the  ovens,  the  grates  and  the  fire-room  floor. 

Plate  I  is  a  section  through  one  oven  and  boiler,  showing 
the  oven  ash-pit  grate,  holes  for  feeding  tan  into  oven,  fire- 
room  floor,  the  boilers,  steam  drum,  mud  drum  and  door  to 
enter  or  sweep  out  flues  in  boiler.  The  two  sections  of  wall 
marked  "wall"  in  the  plate  are  portions  of  the  walls  of  the 
building,  which  continue  up  and  support  the  roof. 

Plate  II,  figure  2,  shows  the  north  elevation,  in  which  the 
door  through  which  the  tan  is  brought  from  the  leaches  to 
the  fire  room  is  shown  by  the  opening  marked  8x10.  Figure 
1  on  same  plate  shows  two  sections,  one  marked  "  Section  on 


THE  LEATHER  MANUFACTURE.  237 

(A  B)"  being  through  the  oven,  and  the  other  marked  "  Sec- 
tion on  (M  N) "  being  through  the  boilers  and  brick  work 
back  of  oven. 

The  furnace  at  Wilcox  has  been  selected  to  illustrate  this 
article  in  preference  to  a  new  design,  because  it  is  a  furnace 
in  actual  use,  which  gives  perfect  satisfaction,  and  because, 
as  it  has  been  already  built,  the  cost  is  accurately  known.  It 
will  be  seen  that  it  really  consists  of  two  complete  sets  of 
ovens  and  boilers,  the  only  thing  in  common  between  them 
being  the  chimney  and  fire  room.  Each  pair  of  ovens  has 
its  own  set  of  boilers,  its  own  feed  water  tank  marked  "  T  "  and 
"T"in  figure  1,  plate  III.  Either  pair  of  ovens  would  be 
nearly  large  enough  to  supply  steam  to  run  the  whole  tannery 
if  the  other  pair  were  stopped,  either  by  accident  or  for  repairs. 
In  case,  however,  only  one  pair  of  ovens  were  used,  it  would 
prob  tbly  be  necessary  to  burn  nearly  all  the  'baric  Jeached, 
while,  when  both  pairs  are  used,  it  is  only  necessary  to  burn 
about  one-half  the  bark.  Each  pair  of  these  ovens  is  prob- 
ably capable  (if  forced  to  the  utmost)  of  burning  one  and  a 
half  cords  of  wet  spent  tan  per  hour,  which  would  evaporate 
9,000  pounds  of  steam,  being  equivalent  to  about  180  horse 
power.  In  actual  practice  at  Wilcox  they  burn  one-half  a 
cord  of  wet  spent  tan  each,  each  pair  of  ovens  per  hour  evap- 
orating 8,000  pounds  of  water,  being  equivalent  to  160  horse 
power  from  both  ovens.  This  steam  runs  the  whole  tannery, 
except  the  rolling  loft. 

The  foundations  of  the  ovens  and  chimney  are  not  shown 
in  the  plans.  They  should  be  of  stone  and  should  go  down 
in  the  ground  below  the  action  of  the  frost.  The  foundation 
under  the  chimney,  on  account  of  the  great  weight  it  has  to 
bear,  should  go  deeper  than  this,  or  at  least  six  feet  below 
the  original  surface  of  the  ground,  and  should  be  a  foot 
larger  than  the  base  of  the  chimney  all  around.  The  first 


288  THE  LEATHER  MANUFACTURF, 

step  in  the  construction  of  this  furnace  would  be  to  mark 
out  on  the  ground  an  area  two  feet  larger  each  way  than  the 
outline  of  the  building,  and  then  excavate  all  the  earth  from 
this  space  three  feet  deep.  Next,  on  the  bottom  of  this  ex- 
cavation, mark  out  the  position  of  the  walls,  and  dig  a  trench 
two  and  a  half  feet  wide  and  two  and  a  half  feet  deep  under 
each.  Thus  there  would  be  four  trenches  under  the  four 
walls  of  the  building,  and  in  addition,  four  trenches  parallel 
to  the  side  walls  under  the  four  dividing  walls  of  the  ovens 
and  boilers.  The  foundation  for  the  chimney  will  come  in 
the  center,  and  should  be  fourteen  feet  square  and  go  down 
four  feet  below  the  bottom  of  the  excavation,  or  seven  feet 
below  the  original  surface  of  the  ground.  The  foundations 
under  the  two  wings  containing  the  feed-water  tanks  may  be 
two  feet  wide,  and  sunk  three  feet  below  the  original  surface 
of  the  ground.  The  walls  of  the  ovens  are  commenced  on 
these  foundations,  three  and  a  half  feet  thick,  but  with  a 
batir  of  one  foot  in  the  hight  from  the  foundation  up  to  the 
level  of  the  fire  room  floor.  From  this  point  they  are  per- 
pendicular, and  of  a  uniform  thickness  of  sixteen  inches.  At 
the  fire  room  floor,  therefore,  the  oven  walls  are  two  and  a 
half  feet  thick.  The  walls  of  the  feed-water  tank  rooms  may 
be  sixteen  inches  thick. 

The  dividing  wall  between  the  ovens  has  a  uniform  thick- 
ness of  one  foot  ten  inches  up  to  the  level  of  the  grate  bars. 
The  fire  brick  linings  of  the  ovens  commence  at  the  level  of 
the  grates,  and  are  set  back  two  inches  on  each  side  to  leave 
a  shoulder  for  the  grate  bars  to  rest  on.  The  grate  bars  are 
each  three  feet  long.  One  end  rests  on  this  shoulder,  and 
the  other  on  a  wrought  iron  bar  (a  worn  out  piece  of  railroad 
track  answers  very  well),  which  runs  the  whole  length  of  the 
furnace,  and  is  embedded  on  the  walls  at  each  end.  There 
are  four  one  and  one-quarter  inch  iron  rods,  each  twenty 


THE  LEATHER  MANUFACTURE.  239 

feet  long,  with  a  thread  and  nut  on  each  end,  and  cast  iron 
washers,  through  each  oven,  under  this  bearing  bar,  to  tie  the 
side  walls  together.  The  whole  inside  of  the  ovens,  and  the 
tops  of  the  bridge  walls,  and  the  inside  of  the  walls  under 
the  boilers,  are  lined  with  fire  brick.  The  holes  for  feeding 
t^e  tan  through  the  top  of  the  arch  into  the  oven  are  lined 
w!th  fire  brick  which  must  be  made  of  the  required  shape  by 
the  manufacturer.  The  side  walls  of  the  ovens  rise  verti- 
cally for  one  foot,  and  are  then  turned  into  a  circular  arch  of 
three  feet  radius.  The  lining  of  this  arch  should  be  of  fire 
brick  not  less  than  six  inches  thick,  and  there  should  be  in 
addition  two  courses  of  common  brick,  so  that  the  whole 
thickness  of  the  arch  is  fourteen  inches.  The  fire  room  floor 
may  be  of  brick,  laid  on  edge,  and  the  space  between  the 
arches  under  the  floor  filled  up  with  broken  bricks  and  mor- 
tar. There  are  four  doors  through  each  outside  wall  of  the 
ovens.  These  must  be  made  with  arched  tops  of  fire  brick, 
made  the  exact  shape  by  the  manufacturer. 

The  owner  of  the  furnace  will  find  it  to  his  advantage  to 
have  the  brickwork  around  the  ovens  constructed  with  great 
care,  as  if  carelessly  built  it  will  crack,  or  even  fall  down,  in 
a  few  years.  The  heat  in  one  of  these  tan-burning  ovens, 
although  not  so  great  as  in  <&  coal  fire,  is  greater  than  in  the 
ordinary  furnace  when  the  grate  to  burn  the  coal  is  under  tJie 
hoikr.  A  plan  of  the  grate  bar  to  be  used  is  shown  in  figure 
3,  plate  V.  These  grate  bars  may  be  much  lighter  than 
when  used  for  coal.  The  oven  doors  should  each  have  a 
register  in  them,  to  be  partly  opened  to  admit  air  above  the 
fire  when  the  oven  is  in  use. 

Through  the  courtesy  of  Mr.  Judson  Schultz,  of  Wilcox, 
Pa.,  I  am  enabled  to  exhibit  the  exact  cost  of  this  furnace  in 
1872.  At  the  present  time  (September,  1876)  the  cost  would 
probably  be  25  per  cent.  less. 


240  THE  LEATHER  MANUFACTURE. 

COST  OF  FURNACE  AT  WILCOX,  1872. 

Brickwork — 

Chimney— 35,000  bricks,  at  $6  00 $210  00 

Two  masons,  20  days,  at  $5  00  per  day 200  00 

Three  helpers,  20  days,  at  $1  50 90  00—   $500  00 

Ovens  and  Walls— 112,500  common  brick,  at  $6  00 675  00 

5,800  fire  brick,  at  $60  00 348  00 

One-quarter-circle  bricks,  for  arch 100  00 

Three  masons,  52  days  each,  at  $5  00  per  day 780  00 

Two  helpers,  50  days  each,  at  $1  50  per  day. 150  00 

Digging  foundations,  hauling  stone  and  sand 300  00—  2,353  00' 

Boilers  Etc.— 

Six  boilers  and  standards,  with  two  mud  drums 3,575  57 

Four  furnace  doors,  four  back  connection  doors,  four  doors 
to  enter  under  boiler,  two  smoke  jacket  doors,  one 

chimney  door,  5,536  fts,  at  5%c 303  48 

Back  stays,  8,062  fi>s,  at  5c 403  10 

2,048  grate  bars,  26,175  fts,  at  4%c 1,177  88 

Washers,  130  fts,  at  5%c 7  15 

Dampers  and  smoke  jacket 58  00 

Tie  rods  under  grate 100  00—  2,049  61 

Eoof- 

3,000  feet  of  lumber  for  rafters,  at  $10  00 30  00 

Labor 50  00 

Sheetiron 325  00—     405  00 

Total  cost  of  oven  and  fixtures $8,883  18 

Taking  the  total  cost  at  $7,000,  it  will  appear  that  the 
original  investment  in  the  furnaces  will  be  at  the  rate  of  7 
cents  for  each  hide  tanned  annually,  and  that  at  15  per  cent, 
(allowing  7  per  cent,  for  interest  on  capital,  3  per  cent,  foi 
annual  repairs,  and  5  per  cent,  for  a  sinking  fund),  the  annual 
cost  will  be  $7,OOOX.15:=$1,050,  or  about  one  cent  for  each 
hide  tanned. 

If  it  were  required  to  build  a  cheaper  furnace  than  that  at 
Wilcox,  the  brick  walls  above  the  ovens  and  boilers  and  the 
iron  roof  may  be  omitted,  and  wooden  walls  and  a  wooden 
roof  used  in  their  stead. 

If  tubular  boilers  in  place  of  flue  boilers  are  used,  the  cost 
of  the  boilers  will  be  less,  and  the  brickwork  setting  will  cost 
less. 

If  the  feed  water  is  free  from  sediment  and  scale,  tubular 
boilers  will  be  just  as  economical  as  flue  boilers,  but  will  not 


THE   LEATHER  MANUFACTURE.  241 

List  so  long,  and  will  need  more  unremitting  attention  on  the 
part  of  the  engineer  to  keep  the  water  at  the  correct  level. 
On  the  whole,  they  are  not  to  be  recommended. 

Plates  IV,  V,  VI,  represent  an  oven  for  burning  wet  spent 
tan  when  the  tan  is  shoveled  in  to  the  oven  through  an 
ordinary  furnace  door  like  coal  or  wood. 

P  ate  V  is  a  section  through  the  center  of  oven  and  middle 
boiler,  showing  the  oven  grate  and  ash  pit,  the  boiler,  steam 
and  mud  drum,  and  the  front  and  back  connections. 

Plate  VI,  figure  1,  represents,  on  the  left  hand  portion,  an 
elevation  of  the  front  of  the  oven,  showing  one  furnace  and 
one  ash  pit  door  and  half  of  the  middle  furnace  door,  and  on 
the  right  hand  portion  a  section  through  the  oven  showing 
the  top  and  sides  of  the  oven,  the  thickness  of  the  brickwork 
and  the  grate  bars.  Figure  2  is  a  section  through  the  boiler, 
back  of  the  oven,  showing  the  three  boilers  and  flues,  the 
steam  and  mud  drum  and  the  thickness  of  the  brickwork. 
The  unshaded  bricks  represent  the  fire  brick  in  all  three 
plates.  Furnaces  fed  from  the  front  like  this  are  generally 
considered  cheaper  to  build  than  those  fed  from  the  top,  but 
this  is  because  they  are  generally  made  smaller  in  proportion 
to  the  size  of  the  tannery  than  those  fed  from  the  top,  and 
are  therefore  ordinarily  much  less  efficient. 

If  both  furnaces  are  built  of  the  size  required  to  give  the 
best  results,  the  furnace  fed  from  the  front  will  require  to  be 
the  largest  and  will  cost  the  most. 

The  construction  will  be  readily  understood  from  the  plans. 
The  plan  of  the  grate  shown  in  figure  3,  plate  V,  has  been 
found  in  practice  to  be  strong  enough.  There  are  two  lengths 
of  these  grate  bars,  each  2  feet  8J  inches  long.  The  back 
length  is  level,  but  the  front  length  should  be  raised  from  six 
to  eight  inches  in  front  to  facilitate  feeding  the  tan  toward 
the  back.  The  ends  of  the  grate  bars  must  be  carried  by 

16 


242  THE  LEATHER   MANUFACTURE. 

wrought  iron  bars,  reaching  across  the  oven  and  built  into 
the  brick  work  at  each  side.  An  old  piece  of  railroad  iron 
will  answer,  or  a  piece  of  wrought  iron  four  inches  deep  and 
one  inch  thick. 

The  furnace  and  ash  pit  doors  may  be  made  of  a  piece  of 
boiler  iron  a  quarter  of  an  inch  thick,  with  the  hinges  and  latch 
riveted  on.  The  lugs  to  carry  the  hinges,  and  the  latch,  may 
be  built  into  the  brick  wall,  thus  dispensing  with  the  cast 
iron  door  frames.  The  furnace  door  should  be  double,  the 
inner  lining  of  boiler  plate  being  punched  full  of  quarter  inch 
holes  two  inches  apart.  Both  the  ash  pit  and  the  furnace 
doors  should  have  openings  through  them  with  registers. 

The  three  furnace  doors  should  be  each  20  inches  wide  and 
18  inches  high  on  the  outside,  spreading  out  wider  on  the 
inside,  as  shown  in  the  plan,  plate  IV.  The  ash  pit  doors 
should  be  16  inches  wide  by  24  inches  high  in  the  clear.  The 
fire  room  floor  should  be  24  inches  below  the  sil  of  the  fur- 
nace door,  or  18  inches  above  the  bottom  of  the  ash  pit,  as 
the  fireman  can  shovel  in  the  tan  easier  than  if  the  floor  is 
as  low  as  the  bottom  of  the  ash  pit. 

The  brick  work  around  the  oven  must  be  tied  up  with  buck 
stays  and  iron  rods,  as  shown  in  the  plans,  for  as  the  arch 
over  the  top  of  the  oven  has  a  wide  spread,  it  exerts  a  great 
pressure  on  the  side  walls.  Also  the  fire  bricks  in  the  arch 
must  be  laid  with  care  with  narrow  joints,  or  they  will  fall  out 
after  the  furnace  has  been  a  little. while  in  use. 

The  smoke  connection  in  this  furnace  is  shown  in  plate  V> 
as  built  of  brick  running  across  the  boilers  over  the  top  of 
the  oven.  This  connection  must  lead  to  the  chimney  built 
on  either  side.  The  chimney  should  be  eighty  feet  higli  and 
twenty-four  inches  in  diameter.  The  bac'v  ends  of  the  boiler 
are  carried  by  the  mud  drums,  and  the  front  ends  by  a  piece 
of  railroad  iron  built  into  the  brick  work  over  the  oven. 


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THE  LEATHER  MANUFACTURE . 


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THE   LEATHER  MANUFACTURE. 


245 


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ILLUSTRATIONS. 


248  THE  LEATHER  MANUFACTTJKF. 

Until  within  a  few  years  it  lias  been  considered  indispen- 
sable that  the  "  sweat  pits  "  of  the  tanner  should  be  under 
ground,  but  now  they  are  placed  on  the  top  of  the  ground, 
with  earth  or  some  other  non-conductor  surrounding  and 
covering  them.  It  is  far  more  desirable  that  the  bottom  of 
the  pit  should  be  on  a  level  with  the  beam  house  floor,  or 
so  nearly  so  that  a  wheelbarrow  can  be  run  from  one  to 
the  other,  than  that  there  should  be  an  earth  or  rock  excava- 
tion surrounding  the  pit  as  was  formerly  thought  necessary. 
The  present  plan  enables  the  pits  to  be  properly  lighted  both 
from  the  ends  and  tops. 

These  pits  should  be  large  enough  to  properly  hang  one 
pack  each,  whatever  may  be  the  size  of  that  pack — usually 
from  100  to  200  sides.  The  ceiling  should  be  at  least  eight, 
and  if  ten  feet  high  all  the  better.  There  should  be  a  space  of 
at  least  two  feet  from  the  lower  portion  of  the  sides,  while 
hanging,  to  the  floor,  for  the  purpose  of  allowing  the  free  in- 
troduction of  steam  under  the  pack,  if  the  pit  is  too  cold,  and 
of  cold  spring  or  well  water  if  too  warm.  The  temperature 
should  be  about  60  to  70  degrees.  The  air  should  never  be 
dry,  but  kept  moist  by  the  introduction  of  steam  or  cold  water. 
Usually  the  atmosphere  wiU  regulate  itself.  The  wet  pack, 
hung  in  an  atmosphere  of  65  degrees,  will  impart  its  moisture, 
which  will  condense  so  that  drops  of  cold  water  will  stand 
on  the  surface  and  show  on  the  hair  of  the  hide,  precisely  as 
from  the  ox  when  profusely  sweating  from  over  exertion. 

The  mode  of  hanging  will  vary  with  the  judgment  of  the 
tanner.  Some  hang  over  sticks,  others  hang  from  tenter 
hooks.  .But  whatever  way  hung,  the  sides  or  hides  should 
be  so  placed  that  the  attendant  can  readily  reach  each  side, 
so  that  as  soon  as  the  hair  of  even  one  side  or  hide  begins 
to  "  come  "  it  should  be  dropped  to  the  bottom,  and  when 
that  of  a  majority  of  the  pack  "  starts  "  they  should  be  re- 


THE  LEATHER   MANUFACTURE. 


240 


VIEW  IN  PERSPECTIVE — SHOWING  INSIDE  OF  TWO  END  PITS. 


INTERIOR  VIEW  OF  SWEAT  PIT. 


250  THE   LEATHER   MANUFACTURE. 

moved  ;  but  if  proper  care  has  been  taken  to  have  the  whole 
pack  in  the  same  condition  and  of  the  same  weight  and  sub- 
stance the  whole  pack  will  come  out  about  the  same  time. 
From  five  to  seven  days'  time  will  sweat  an  ordinary  dry  hide 
in  one  of  these  pits.  The  ventilation  of  these  pits  should 
always  be  under  the  control  of  the  attendant. 

One  of  the  views  presented  gives  a  lengthwise  view  of  sev- 
eral pits,  and  the  other  that  of  a  single  pit  as  seen  from  the 
door. 

THE  "SHOVER"  HIDE  MILL. 

The  three  sectional  plates  herewith  given  present  a  fairly 
intelligent  working  plan  of  the  ordinary  "  fulling  stocks  "  for 
softening  hides.  This  form  of  mill  has  so  completely  taken 
the  place  of  the  old-fashioned  "  falling  stocks  "  as  to  render  it 
unnecessary  to  present  a  drawing  of  that  discarded  machine. 
The  capacity  or  power  of  this  mill  to  soften  dry  hides  is 
almost  without  limit.  One  mill  of  the  size  here  contemplated, 
run  at  the  rate  of  sixty  to  eighty  revolutions  per  minute,  will 
soften  1,000  hides  of  ordinary  weight  in  one  week,  running 
for  twelve  hours  per  day.  It  is  within  the  writer's  knowledge 
that  a  mill  of  this  description  has  been  made  to  soften  100,- 
000  dry  hides  in  one  year,  being  run  night  and  day. 

In  the  drawing  this  mill  is  geared  from  above,  but  the 
power  is  often  attached  from  beneath,  and  where  this  can  be 
done  it  has  the  advantage  of  greatly  facilitating  the  workmen 
in  feeding  the  mill  and  handling  the  hides.  With  the  latter 
attachment  the  arms  of  the  mill  are  extended  down  through 
the  hammers,  and  the  bottom  of  the  mill  and  driving  shafts 
are  attached  below,  just  as  they  are  represented  in  the  draw- 
ing to  be  attached  above.  These  mills,  as  formerly  made, 
of  hard  wood  plank,  would  wear  out  with  one  year's  constant 
service;  but  lined  and  faced  with  cast  and  wrought  iron,  as 


THE  LEATHER  MANUFACTURE. 


251 


THE  HIDE  MILL. 


252  THE  LEATHER  MANUFACTURE. 

is  now  customary,  they  will  last  for  many  years.  The  form 
of  the  mills  varies  slightly  with  the  different  makers,  and 
the  size  as  well.  Tanners  who  are  about  to  adopt  this  method 
of  softening  hides  will  do  well  to  examine  with  care  the  most 
approved  angles  and  motion  of  mills  now  in  use  in  our  best 
yards.  The  double  action  of  these  mills  is  as  well  adapted 
for  skins  and  pelts  of  all  kinds  as  for  dry  hides.  There  can 
be  no  doubt  that  from  this  form  of  mill  the  idea  of  the  mod- 
ern "washing  machine"  was  taken,  and  in  turn  the  tanner 
is  indebted  to  the  clothiers,  and  chamois  and  oil  dressing 
leather  manufacturers  for  the  ideas  contained  in  this  most 
efficient  hide  softener,  for  with  some  variations  of  form  it  is 
a  reproduction  of  the  fulling  stocks  of  the  clothier  a  century 
ago.  It  was  introduced  among  American  tanners  about  the 
year  1830,  at  Salem,  Mass.,  and  did  not  find  general  accept- 
ance among  hemlock  tanners  in  the  State  of  New  York  until 
1850. 

THE   HAND   REEL. 

On  the  opposite  page  will  be  found  a  representation  of  a 
hand  reel,  which  is  commended  in  Chapter  YIL,  on  "  hand- 
ling." The  facility  with  which  packs  may  be  thus  trans- 
ferred from  one  vat  to  another  commends  this  skeleton  reel 
to  all  tanners.  It  is  safe  to  estimate  the  performance  of  this 
machine  with  two  men  as  equal  to  that  of  six  men  by  the  old 
hand  process.  Besides,  it  does  not  require  either  man  to 
stoop  in  his  work,  and  the  labor  is  therefore  much  easier. 
The  stand  and  skeleton  drum  should  be  made  of  as  light 
material. as  possible,  so  that  its  transfer  from  one  vat  to 
another  may  be  effected  by  the  two  men  with  ease.  As  there 
need  be  but  one  of  these  reels  in  any  ordinary  sized  tannery, 
the  tanner  can  well  afford  to  have  the  frame,  drum  and  bear- 
ings made  of  substantial  but  light  material  well  adjusted  in 


THE  LEATHER  MANUFACTURE. 


253 


I 


254  THE  LEATHER  MANUFACTURE. 

all  parts,  even  with  brass  bearings.  The  whole  need  not 
cost  over  ten  dollars. 

If  still  more  ecouomy  of  labor  is  required,  these  reels  may 
be  driven  by  power  from  shafting  and  pullies  perrnanentlv 
running  overhead.  But  it  will  be  found  that  two  men  can 
shift  ten  thousand  sides  in  ten  hours  without  the  use  of 
power. 

The  sides  may  be  tied  together  with  strings  or  connected 
with  a  tie-loop ;  strings  are  preferable,  and  are  quite  inex- 
pensive. 

THE  ROCKER  HANDLER. 

The  accompanying  drawing  will  serve  to  give  a  correct 
idea  of  the  rocker  handler,  which  is  now  held  in  such  high 
esteem. 

The  gentle  and  intermittent  motion  required  should  be 
given  .from  shafting  from  above.  This  shafting  should  run 
over  the  center  aisle,  and  have  projecting  arms,  from  which 
there  should  extend  a  connection  to  each  of  the  frames  of  the 
rockers.  This  connection  may  be  by  a  pole  or  strip  of  plank 
two  inches  square,  made  of  any  tough  timber,  and  so  ad- 
justed as  to  be  readily  disconnected.  The  vibration  of  the 
rocker  on  which  the  leather  is  hung  should  not  be  over  four 
or  six  inches,  thus  causing  as  little  agitation  of  the  liquor  as 
is  consistent  with  a  gentle  movement  of  the  fiber  of  the  green 
stock.  (See  Chapters  VII.  and  YIII.) 


THE  LEATHER  MANUFACTURE. 


255 


256  THE   LEATHER  MANUFACTURE. 


THE  AMERICAN  LEATHER  ROLLER. 

The  skeleton  drawing  on  the  opposite  page  represents  the 
universal  American  roller.  The  only  patent  now  existing  on 
this  roller,  as  here  presented,  is  on  the  leverage  under  the 
table.  The  whole  cost  of  this  leverage  is  $30,  on  which  there 
may  be  a  profit  of  $10  for  the  patentee.  The  roller  bed  is 
made  of  wood  or  rnetal ;  the  one  in  the  drawing  is  made  of 
copper.  It  is  cast  hollow,  and  is  valued  at  about  $40.  The 
whole  machine  will  cost  about  $200,  including  the  woodwork, 
table,  etc.  Such  a  machine  will  roll  about  100  sides  each  day 
of  ten  hours. 

The  amount  of  pressure  which  can  be  brought  to  bear  on 
the  side  has  absolutely  no  limit.  It  is  claimed  that  a  side  of 
sole  leather  can  be  cut  in  two  if  the  whole  power  of  the  lever 
is  evoked. 


THE  LEATHEB  MANUFACTURE. 


257 


17 


258  THE  LEATHER   MANUFACTURE. 

The  representation  on  the  opposite  page  shows  the  new 
form  of  dryer,  now  so  generally  in  use.     The  building  may 
be  of  any  hight  or  shape  ;  the  engraving  is  of  a  structure  of 
four  stories,  besides  the  basement  floor.     This  lower  story 
should  be  reserved  for  steam  pipes,  or  other  means  of  head- 
ing.     All  the    floors    above    are  latticed,   and    when    not 
obstructed  by  dampers,  allow  the  free  passage  of  air  to  the 
top  opening.     The  draft  may  be  regulated  by  "stops"  or 
"dampers,"  either  at  the  openings  on  the  lower  floor  or  at 
the  top  openings,  or  both,  the  object  being  to  absolutely  con- 
trol the  currents  of  air,  so  ll  at  only  so  mucJ),  and  at  such  periods 
as  the  attendant  may  desire,  icilJ  air  le  alloiced  to  pass.    If 
glass  windows  are  used,  as  shown  in  the  drawing,  they  are 
only  to  give  light  to  enable  the  work  to  be  done,  but  never 
to  be  opened  for  the  purpose  of  admitting  air  or  light  to  reach 
the  leather,  and  when  the  work  is  done  they  are  to  be  covered 
with  a  window  shade,  so  that  the  leather  may  be  excluded  from 
the  light  during  the  whole  drying  process.   This  form  of  dryer 
is  built  on  the  plan  of  a  chimney,  and  the  laws  of  its  action 
are  precisely  like  those  of  that  essential  ventilator  to  our 
dwellings ;  if  currents  are  peimitted  to  enter  otherwise  than 
at  the  bottom,  counter  currents  will  be  formed  in  the  dryer, 
and  it  will  not  "  draw,"  but  if  the  air  is  confined,  then  the 
difference  between  the  temperature  of  the  air  at  the  ground 
and  that  at  the  elevation  at  the  outlet  will  cause  the  current 
to  rise,  and  rapidly  just  in  proportion  .to  its  hight.     Hence, 
to  get  a  satisfactory  self-acting  turret,  the  building  should  be 
as  high  as  possible.     For  more  specific  suggestions  regarding 
the  economic  use  and  management  of  these  dryers  see  Chap- 
ter xn. 


THE  LEATHER  MANUFACTURE.  259 


THE  TURRET  DRYER. 


260  THE   LEATIIEU   MANUFACTURE. 

THE  ALLEX   &  WARREN   SPRINKLER  LEACH, 

This  is  a  "percolating"  process  of  leaching  bark  in  con tra- 
aistinction  from  the  "  press  "  system.  Both  methods  are  in 
very  general  use  in  this  country.  The  Allen  &  Warren 
method  is  known  as  the  "  sprinkling"  process,  and  is  shown 
in  the  drawings.  Many  tanners,  however,  accomplish  imper- 
fectly a  similar  result  by  flooding  their  leaches  with  a  limited 
quantity  of  liquor,  allowing  it  to  percolate  through,  and  then 
flooding  again  and  again,  each  time  with  about  one-third  of 
a  vat  of  liquor.  But  if  percolation  is  to  be  practiced  at  all, 
there  can  be  no  doubt  that  the  Allen  &  Warren  method  is  to 
be  preferred. 

This  sprinkling  process  has  been  so  much  abused  by  tan- 
ners, and  so  much  damage  has  been  done  thereby,  both  to  the 
color  and  general  quality  of  the  leather,  that  a  strong  preju- 
dice exists  in  the  minds  of  many  against  this  method  of  leach- 
ing ;  but  it  is  believed  that  if  the  new  bark  is  leached  with  cold 
or  only  warm  water  or  liquor,  then  a  concentrated  and  pure 
liquor  can  be  obtained,  while  if  the  head  liquor  is  heated  up 
to,  or  near,  the  boiling  point,  and  is  then  sprinkled  on  the 
new  bark,  an  undue  amount  of  coloring  matter  will  be  carried 
down  and  find  its  place  on  the  leather,  making  both  a  dark 
color  and  a  harsh  texture  and  fiber.  The  practical  working 
of  these  leaches  proves  that  "strength"  can  be  more  concen- 
trated with  them  than  by  any  other  means;  hence,  for  extract 
manufacturing,  they  are  serviceable,  and  we  should  judge 
that  fully  one-half  of  the  hemlock  tanners  of  the  country  are 
using  them,  without  appreciating  their  good  qualities  or 
avoiding  their  bad  ones. 

The  heater  box,  by  which  the  exhaust  steam  from  an  en- 
gine will  heat  a  constant  stream  of  water  or  liquor  without 
in  the  least  reacting  upon  or  retarding  the  power  of  the  en- 
gine, may  be  seen  in  the  two  lower  engravings.  The  sec- 


THE  LEATHER  [MANUFACTURE. 


2G1 


THE  SPRINKLER  LEACH. 
g 


11      W 

PAN  FOR    HEATING  LIQUORS — SECTIONAL  VIEW. 


TAN  FOR   HEATING  LIQUORS — INCLOSED. 


262  THE  LEATHEU   MANUFACTURE. 

tional  figure  represents  two  shelves,  c  and  d.  These  are  set 
on  an  incline,  so  that  the  water  or  liquor,  which  enters  at  «, 
tills  the  compartment  b,  until  it  overflows  on  the  inclined 
shelf  c,  passes  down  on  the  inclined  shelf  d,  and  so  finally 
out  of  the  discharge  opening  e.  The  steam  from  the  engine 
takes  the  opposite  course,  entering  at  /,  passing  through  the 
liquor  or  water  until  it  finds  its  way  out  at  g.  The  steam 
thus  passing  will  fully  condense,  and  only  moderately-heated 
air  will  pass  off.  The  other  drawing  represents  the  enclosed 
box,  with  these  shelves  inside. 

By  this  simple  and  inexpensive  construction  of  plank  a 
most  effective  heater  is  made,  and  by  its  use  a  constant 
stream  of  hot  water  or  liquor  can  be  run  through  on  to 
the  leaches. 

If  the  most  perfect  heater  possible  is  desired  then  small 
holes  may  be  made  in  the  shelves,  in  which  case  they  should 
be  made  of  copper  plates — then  the  perforations  can  be  small 
and  effective ;  they  will  rain  down  small  drops,  condensing 
the  steam  most  perfectly.  This  is  one  of  the  best  and  most 
effective  improvements  ever  made  in  the  heating  of  liquors. 
There  is  no  patent  claim  on  this  improvement. 

THE  BABE  CUTTING  MACHINE. 

The  accompanying  cut  is  designed  t  >  show  the  new  mn- 
chine  for  sawing  tanners'  bark.  There  can  be  no  doubt  that 
this  machine  does  prepare  bark  for  leaching  better  than  any 
known  bark  mill  of  ordinary  construction.  It  will  saw  damp 
or  even  wet  bark  with  the  same  facility  as  if  it  were  dry.  If 
the  bark  is  in  large  pieces  it  can  be  fed  into  the  mill  with 
facility,  but  if  small  then  it  will  require  a  hopper  or  some 
other  contrivance  not  yet  perfected,  certainly  riot  practically 
introduced,  to  facilitate  the  feeding.  It  is  claimed  that  a 
single  mill  will  cut  one  cord  and  a  half  per  hour.  To  do 


THE   LEATHER   MANUFACTURE. 


263 


BAEK  CUTTING  MILL. 


264  THE   LEATHER    MANUFACTURE. 

this  we  should  judge  that  the  circumstances  must  be  very 
favorable. 

The  high  cost  of  this  mill,  $300,  will  probably  restrict  its 
use ;  it  is,  however,  far  better  for  tanners  to  pay  even  this 
price,  unless  it  is  possible  to  secure  an  equally  good  result 
by  some  more  economical  method.  That  other  method  is,  in 
our  judgment,  by  the  use  of  a  wire  screen,  as  expressed  else- 
where. There  is  no  excuse  for  attempting  to  leach  coarse 
and  unevenly  ground  bark. 

THE   KEYSTONE   BARK   MILL. 

The  skeleton  form  of  bark  mill  presented  on  the  opposite 
page  is  probably  the  most  skillfully  manufactured  machine 
of  the  kindltnown  to  the  trade.  We  have  taken  special  pains 
to  describe  its  peculiar  construction  and  its  performance 
in  chapter  Y,  to  which  the  reader  is  referred.  Great  pains 
are  taken  to  make  this  mill  run  true ;  the  ability  to  replace 
the  surface  segments,  by  either  steel  or  cast  iron  surfaces, 
renders  it  one  of  the  most  serviceable,  and,  when  we  consider 
the  safety  coupling  with  which  it  is  connected  with  the  driv- 
ing shaft,  it  is  one  of  the  most  durable  mills  known.  If  tan- 
ners either  cannot  or  will  not  adopt  the  wire  screen,  tnen  we 
say  this  mill  will  grind  more  uniformly  than  any  mill  offer- 
ing to  the  public,  but  it  will  not  grind  wet  bark  any  more 
than  will  other  cast  iron  mills. 

THE   HOWARD   SCRUBBER. 

As  the  drawing  indicates,  this  scrubber  consists  of  two 
skeleton  drums,  with  projecting  arms,  into  which  are  fastened 
birch  brooms,  closely  held.  The  drums  are  rolled  together 
by  the  cog  gearing  as  seen  on  the  side.  When  ready  for  work 
the  box  or  covering  marked  A  is  dropped  down,  and  through 
the  slit  or  opening,  G,  the  sides  are  fed.  The  feeding  is  per- 


THE  LEATHER  MANUFACTURE. 


265 


ALLENTOWN  BARK   MILL. 


HOWARD   LEATHER   WASHER. 


266  THE   LEATHER   MANUFACTUIir. 

formed  by  allowing  one  end  of  the  side  to  pass  down  between 
the  revolving  brushes  ;  if  the  side  is  firmly  held  and  allowed 
only  to  pass  down  slowly  the  surfaces  will  be  thoroughly 
scrubbed,  and  well  done  just  in  proportion  to  the  time  al- 
lowed. To  do  the  work  well  each  side  must  be  passed 
through  twice,  once  from  the  head  and  once  from  the  butt. 
One  of  these  machines  with  two  men  to  attend  it  will  scrub 
about  four  hundred  sides  per  day.  It  is  simply  justice  to  say 
that  the  "  drum  scrubber,"  elsewhere  described,  is  taking  the 
place  of  this  Howard  machine  in  some  of  our  large  hemlock 
tanneries,  and  tanners  will  do  well  to  examine  the  merits  ot 
both  before  adopting  either. 

THE   SALEM   WET  TAN   PRESS. 

This  lever  roller  serves  a  most  useful  purpose  for  squeezing 
out  the  remaining  ooze  from  spent  bark,  previous  to  burning 
it.  Just  to  the  extent  that  water  or  spent  ooze  is  taken  from 
the  bark  is  the  bark  rendered  serviceable  to  burn.  It  is  now 
demonstrated  that  Thompson's  patent  for  burning  water, 
(which  is  equivalent  to  saying  that  wet  tan  will  give  more 
heat  than  dry  tan),  is  a  fallacy.  But  whether  the  power  lost 
by  squeezing  out  the  water  is  not  the  equivalent  of  power 
lost  in  drying  out  the  water  in  the  oven  is  a  question  never 
yet  determined  by  actual  experiment. 

This  Salem  machine  is  fully  as  efficient  as  the  French  and 
English  machines  for  the  same  purpose,  and  seems  more  sim- 
ple in  construction.  It  is  regarded  as  serviceable  where  the 
tanner  requires  more  power  than  he  can  gain  by  the  use  of 
wet  spent  tan  burned  in  an  ordinary  oven ;  but  all  sole  lea- 
ther tanners  have  an  excess  of  tan,  and,  therefore,  can  never 
require  this  wet  tan  squeezer. 


THE  LEATHER  MANUFACTURE.  267 


THE  SALEM  TAN  PRESS. 


268  THE   LEATHER   MANUFACTURE. 


THE  LOCKWOOD  AUTOMATIC  LEATHER  SCOURER  AND  HIDE  WORKER. 

On  the  opposite  page  is  an  illustration  of  this  new  inven- 
tion, patented  July  26th,  1876.  The  machine  is  novel  in 
construction,  simple  in  its  movements,  and  ingenious  to  the 
extent  of  almost  running  itself,  as  the  weight  of  a  man's  finger 
can  guide  the  scourer  over  the  surface  of  any  kind  of  thick  or 
thin  leather.  The  patentee  claims  it  to  be  a  machine  complete 
in  itself,  independent  of  building  or  framework ;  it  can  be  set 
up  without  bolting  or  bracing,  is  durable,  being  made  of  metal 
of  the  utmost  strength,  and  with  air  cushions  which  relieve 
the  working  parts  of  thrusts  and  strains.  The  machine  can 
be  set  at  any  angle  with  the  line  of  shafting,  and  belted 
on  either  end  from  above  or  below.  Only  from  one  to  three 
horse  power  is  required  to  run  it,  according  to  the  thickness 
of  leather  being  dressed.  It  occupies  but  little  more  space 
than  an  ordinary  currier's  table.  It  seems  almost  automatic 
in  its  movements,  and  is  capable  of  the  widest  range  of  work, 
from  the  lightest  to  the  heaviest ;  will  scour,  set  out  or  glass, 
and  can  be  made  to  take  a  slow  or  quick  stroke,  a  long  or  a 
short  one,  making  the  most  perfect  stroke  attainable  with 
the  smallest  Joss  of  motion,  which  is  effected  by  the  epi-cycle 
and  cam  combined. 


THE  LEATHER  MANUFACTURE. 


269 


270  THE  LEATHEK  MANUFACTURE. 


THE  FITZHENRY  SCOURING  MACHINE. 

This  machine  has  been  so  universally  adopted,  not  only 
in  this  country  but  throughout  Europe,  that  it  is  perhaps 
doubtful  whether  it  should  not  be  excluded  as  one  of  the  old 
inventions,  too  well  known  to  be  entitled  to  a  place  in  this 
volume,  which  claims  only  to  present  novelties,  or  such  ma- 
chines as  are  confined  in  their  use  to  localities,  and  are  com- 
paratively new.  But  since  within  a  few  years  we  have  an- 
other, and  within  a  few  months  still  one  more,  competitor  for 
the  honors  of  recognition,  all  three  are  given  in  contrast. 


THE  LEATHER  MANUFACTURE. 


271 


272  THE   LEATHER   MANUFACTURE. 


THE  BURDON  SCOURER. 

This  practical  and  very  serviceable  machine  is  mostly  use- 
ful in  scouring  out  bloom,  while  it  at  the  same  time  softens 
and  cleanses  the  grain.  It  is  useful  for  harness  leather  and 
fair  leather  curriers,  but  has  not  so  far  proved  a  success  in 
scouring  sole  and  belt  leathers,  which  require  more  vigorous 
treatment.  For  calf,  sheep  and  goat  it  should  answer  a  most 
valuable  purpose,  and  for  grain  leather  it  must  prove  a  very 
efficient  machine. 

The  high  cost  of  the  machine  has  no  doubt  prevented  its 
adoption  more  generally  by  the  trade.  Had  the  improve- 
ment fallen  into  other  hand*,  there  can  be  no  doubt  that  it 
would  have  come  into  general  use  before  now. 


THE  LEATHER  MANUFACTURE. 


273 


THE  BURDON  LEATHER  SCOURER. 


18 


274  THE   LEATHER   MANUFACTURE. 


THE   STUFFING   WHEEL. 

The  accompanying  drawing  presents  one  of  the  commonest 
forms  of  the  stuffing  wheel,  now  in  very  general  use  in  this 
country.  Through  the  opening  door  may  be  seen  wooden 
pins  on  which  the  leather  falls  in  the  revolutions  of  the 
wheel,  and  they  also  serve  the  purpose  of  carrying  upward 
the  sides  or  skins,  and  generally  agitating  the  fiber.  This 
wheel  may  be  driven  by  a  belt,  as  shown  in  the  drawing,  or 
by  cast  iron  gear. 

The  general  methods  of  using  this  wheel  have  already 
been  discussed  in  the  preceding  chapters.  It  was  first  prac- 
tically introduced  by  Mr.  Charles  Korn,  as  early  as  1856  to 
1860.  It  had  its  origin  in  Germany,  but  there  a  barrel  or 
hogshead  served  the  purpose,  while  here  special  wheels  of 
permanent  construction  were  first  introduced  into  the  curry- 
ing shop  of  Mr.  M.  M.  Schultz,  in  the  year  1860,  at  Sparrow- 
bush,  N.  Y.,  under  the  direction  of  the  original  introducer. 

This  wheel  has  revolutionized  the  character  of  the  upper 
leather  of  the  country,  which  is  now  made  soft  and  yielding, 
whereas  before  it  was  hard,  the  oil  and  tallow  being  now 
fulled  into  the  center  of  the  fiber,  while  under  the  old  method, 
which  applied  the  stuffing  on  the  flesh  side,  it  only  penetrated 
a  little  beyond  the  surface,  leaving  the  main  body  of  the 
leather  dry  and  unaffected.  Leather  prepared  for  this  wheel 
should  be  in  the  same  condition  as  to  dryness  as  if  stuffed 
on  the  surface  in  the  ordinary  way — neither  too  wet  nor  too 
dry. 


THE  LEATHER  MANUFACTURE. 


275 


THE  STUFFING  WHEEL. 


276  THE  LEATHER  MANUFACTUBE. 


OHAELES  KORN'S  WHITENING  MACHINE. 

The  accompanying  illustration  shows  Mr.  Korn's  whitener, 
with  the  inventor  operating  it.  The  action  of  the  machine  is 
precisely  that  of  a  currier's  knife  in  the  hands  of  the  work- 
man by  Ihe  ordinary  beam  process.  The  knives  are  fastened 
to  an  endless  leather  belt,  and  set  diagonally,  so  that  when  the 
cut  is  made  on  the  beam,  as  it  passes  down  in  front  of  the 
operator,  there  is  a  sliding  and  diagonal  cut.  The  knives  (for 
there  may  be  as  many  as  you  please,  certainty  three  or  four) 
are  cleared  on  their  edge  by  one  moving  automatic  finger, 
and  by  an  automatic  hand  the  edge  is  sharpened.  This  lat- 
ter performance  is  the  most  complete  success,  performed  by 
the  most  ingenious  piece  of  mechanism,  the  writer  has  ever 
seen.  Ihe  inventor  claims  that  he  can,  with  this  machine, 
do  the  work  of  four  men,  and  do  it  better  than  by  hand  work. 


THE  LEATHER  MANUFACTURE. 


277 


278  THE   LEATHER    MANUFACTURE. 


THE    "  UNION    LEATHER    WHITENING,    BUFFING    AND    SKIVING    MA- 
CHINE." 

Herewith  is  presented  a  representation  of  a  recently  in- 
vented machine  for  whitening,  buffing  and  skiving  leather. 
It  is  simple  in  construction,  easily  kept  in  order,  requires 
from  four  to  five  horse  power  to  run  it,  according  to  the 
thickness  of  the  leather,  and  requires  only  an  ordinary  oper- 
ator to  perform  as  much  work  in  one  day  by  the  use  of  the 
machine  as  is  usually  done  by  four  whiteners.  The  quality  of 
work  is  uniform  and  equal  to  that  of  the  best  skilled  hand 
labor.  The  knives  or  blades  make  clean  cuts,  leaving  no 
nap,  and  the  leather,  when  finished,  is  smooth  in  the  flanks, 
bellies  and  necks.  The  cylinder  contains  thirty-two  knives 
or  blades,  inserted  spirally,  and  a  sharpener  is  attached, 
which  travels  forward  and  backward  across  the  edges  of 
the  blades.  The  cylinder  revolves  2,780  times  per  minute, 
and  the  pendulum  swings  to  and  from  the  operator  at  a  speed 
of  90  per  minute. 


THE   LEATHER   MANUFACTURE. 


279 


NION   WHITENER   AND   BUFFING   MACHINE. 


280  THE  LEATHER   MANUFACTURE. 


FISK'S  WHITENING  AND  BUFFING  MACHINE. 

The  inventor  claims  that  this  machine  can  and  will  do  its 
work  much  more  economically  and  even  better  than  can  be 
done  by  hand  labor.  Among  its  claimed  advantages  are  the 
following:  "It  is  small  and  compact,"  "runs  with  small 
amount  of  power,"  and  "  the  table  has  a  convex  bed,  and 
thus  bends  the  surface  of  the  leather  from  rather  than  tow- 
ard the  cutter" — "consequently,"  says  the  inventor,  "the 
square  edges  of  the  blades  take  hold  of  the  leather  with  very 
little  pressure,  and  make  a  light,  clean  cut."  Some  certifi- 
cates of  those  who  have  used  the  machine  assert  that  wax 
leather,  measuring  from  nineteen  to  twenty  square  feet  per 
side,  can  be  whitened  by  it  in  from  one  and  a  quarter  to  one 
and  a  half  minutes,  thus  making  about  forty  sides  per  hour. 
This,  no  doubt,  is  an  extreme  performance. 

The  general  resemblance  of  this  machine  to  "  the  union 
leather  whitening  machine,"  presented  on  another  page, 
will  strike  all  who  compare  their  general  structure.  The  dif- 
ference consists  in  the  working  of  the  table,  or  the  feeding  of 
the  knives.  The  knives  themselves,  and  the  form  of  sharpen- 
ing them,  may  be  considered  identical.  There  can  be  no 
doubt  that  this  machine  does  good  work,  and  far  more  eco- 
nomically than  it  can  be  done  by  hand  labor,  so  that  it  will 
probably  share  the  patronage  of  all  tanners  and  curriers  who 
profess  to  study  the  economies  of  their  trade. 


THE  LEATHER  MANUFACTURE. 


281 


FISK'S  WHITENER  AND  BUFFING  MACHINE. 


282  THE   LEATHER   MANUFACTURE. 


"THE  UUION  LEATHER  SPLITTER," 

shown  on  the  opposite  page,  is  too  valuable  to  omit  from  any 
classification  of  American  leather  dressing  machinery.  It 
was  the  pioneer  of  all  the  improvements  made.  While  we  be- 
lieve there  are  yet  patents  maintained  on  some  unimportant 
parts  of  the  machine,  as  a  whole  all  patents  have  long  since 
expired. 

This  machine  has  revolutionized  the  currying  and  finishing 
of  leather  in  America,  and  is  destined  to  do  so  in  every  other 
country.  No  currier  can  afford  to  carry  on  his  business 
without  a  splitting  machine  of  some  kind,  and  this  union 
machine  is  both  the  cheapest  and  simplest  in  construction. 

THE    LAMPEKT  HIDE  WORKER. 

This  eccentric  machine  is  well  designed  for  tmhairing 
hides  or  skins.  The  drum  "A"  revolves  on  the  axis  "B  "  at 
the  center,  rendering  it  unnecessary  to  move  the  hide  side- 
ways, but  by  a  slight  effort  of  the  hand  the  drum  is  rolled 
from  right  to  left,  or  left  to  right.  The  hide  is  drawn  toward 
the  workman  as  the  parts  become  finished,  whether  the 
machine  is  used  as  a  scourer  or  unhairer,  for  it  is  capable  ot 
doing  any  work  which  can  be  done  with  the  worker.  The 
stone  or  slicker  is  held  by  a  steel  spring,  which  in  turn  is 
propelled  by  the  arm  attached  to  the  balance  wheel.  Tlio 
machine  should  be  seen  in  operation  to  be  fully  appreciated. 

Eccentric  motions  are  now  used  very  extensively  in  several 
departments  for  the  finishing  of  leather.  Grain  leather  of 
all  kinds  is  diced,  and  morocco  and  sheepskins  are  glazed 
and  polished,  as  well  as  diced,  by  machines  which  use  eccen- 
tric motion,  with  modifications  of  form  and  action. 


THE  LEATHER  MANUFACTURE. 


283 


UNION  LEATHER  SPLITTER. 


HENRY  LAMPERT'S  HIDE  WORKER. 


284  THE  LEATHER  MANUFACTURE. 


OUTLINE  OF  HIDE  WITH  TRIM  USUALLY  MADE. 
The  cutting  of  the  hide  in  forms  has  become  so  common, 
from  the  demands  of  the  belt,  harness  and  shoemakers,  that 
we  have  availed  of  the  accompanying  cut  to  locate  each  part 
by  a  designated  term.  This  nomenclature  conforms  in  part, 
if  not  altogether,  to  the  English  classification.  " A  A"  are 
the  bellies;  "B  B"  are  the  bends;  "  0"  and  "Z>"  are 
shoulders.  Sometimes  the  shoulders  are  cut  so  as  to  in- 
clude the  neck,  and  in  that  case  both  (:  C"  and  "  D  "  are  cut 
in  one  piece,  but  it  is  more  common  to  cut  "  C  "  as  the  shoul- 
der. This  trim  will  be  varied  by  the  fact  as  to  whether  the 
hide  is  a  "cut"  or  "stuck"  throat.  The  term  "offal"  ap- 
plies to  all  the  parts  outside  of  the  bends  marked  "  B  B" 
but  the  pieces  are  separately  and  specifically  named  as 
above. 


THE  LEATHER  MANUFACTURE. 


285 


V 


OUTLINE  AND   TRIM  OF  HIDE. 


286  THE   LEATHER   MANUFACTURE. 


TANNERS'  AND  CURRIERS'  TOOLS. 

On  the  following  page  is  a  representation  of  a  case  show- 
ing the  principal  kinds  of  tanners'  and  curriers'  tools  in  use. 
The  center  piece  is  a  moon  knife,  and  around  this  the  others 
are  arranged,  in  most  attractive  form.  The  two  long,  thin, 
straight  knives,  extending  from  the  center  toward  the  right 
and  left  hand  upper  corners,  are  the  recently  introduced  Ger- 
man fleshers,  which  have  of  late  attracted  so  much  attention. 


THE  LEATHER  MANUFACTURE. 


287 


TANNERS'  AND  CURRIERS'  TOOLS. 


Plate  1, 


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Plate    II. 


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13 


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Plate  III. 


Plate  IV. 


Plate  Y 


Plate  VI. 


DESIGN  FOR  FURNACE  FOR  BURNING  "WEST:SPENT-TAN 


^--m-.™-_-.-,,=,™: ,_, 


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66 


c/foss  •  sec  r/o  <v 


INDEX. 


Acid,  use  of  in  handling 76 

in  old  liquors 83 

Agitation  of  the  fiber  of  hides  and 

skins  promotes  rapid  tanning .  183 

Alkali  for  removing  white  spots 90 

Ammonia  in  old  limes 32 

Army  officers,  prejudice  against  hem- 
lock leather 107 


"Baggy"  leather  made  by  vacuum 
tanning 182 

Bark  dust 51 

to  suppress 139 

Bark  elevators  choking 139 

Bark,  extractive  and  coloring  matter 

with  tannin  in 55 

Bark  grinding 46 

it  should  be  ground  fine  and  even  47 

grinding  damp  or  wet  bark 50 

screening  ground  bark 50 

proper  degree  of  fineness 51 

hemlock. .  156 


Bark  rossing 141 

oak 159 

Bark  mills— the  "double  grinder"  .  4s 

the  Allentown  mill 49,  2C5 

the  saw  cutting  mill 51,  2G2 

crushing  machine 52 

capacity  of  different  mills 53 

speed  to  run  mills 53 

Bating  with  warm  water   and   hen 

manure 34 

after  liming 81 

Beam  work 38 

Blacking,  flesh 221 

"Black  rot "  in  sole  leather 89 

Bleaching  leather 100 

Birch  bark  tanning 169 

Boot  and  shoe  industry  of  the  United 
States  according  to  the  census 

of  1870 244 

Box  vats 122 

"  Buffalo"  vats 121 

Buffing  and  whitening  machines 

41,  276,  278,  280 

Buff  leather 210 

Burning  wet  spent  tan,  the  first  suc- 
cess in 147 

Burning  wet  tan 47,  224 


302 


INDEX. 


Calfskins,  French  and  German 194 

the  best  goods  made  sent  to  Great 

Britain  and  the  U.  S 195 

care  in  assorting  the  green  stock.  195 

soaking  and  milling 196 

breaking  the  nerve 197 

liming  andunhairing 198 

bating 199 

coloring  and  handling 200 

laying  away,  grain  to  grain 200 

excluding  the  grain  from  the  air.201 

flesh  shaving 202 

scouring 203 

stuffing 204 

slicker  whitening 205 

boarding 205 

kept  in  russet  state 206 

palm  oil  used  in  currying 207 

Census  of  1870,  boot  and  shoe  indus- 
try of  the  United  States 244 


leather  industry  of 
States  in  1870..., 


the  United 


245 

Chimney,  dimensions  of  for  wet  tan 

ovens 229 

Clay  for  a  tannery  foundation 119 

Clewer,  James',  method  of  leaching.  .  57 
Climate  and  food,  effect  of  on  hides. .  189 
Color,  a  natural  hemlock  desirable. . .  105 
Color  of  hemlock  leather  improved  by 

sumac 101 

Coloring  and  resinous  matter  in  bark  56 
Coloring  of  leather  to  be  done  in  the 

handlers 108 

Concentrated  liquors  obtained  by  the 

sprinkler  leach 66 

Conductors  of  liquor  decay  rapidly 

when  above  ground 124 

Cost   of  boiler   for  20,000-side  tan- 
nery  231 

Cost  of  furnace  at  Wilcox,  Pa 240 

Cost  of  tanning,  the 169,  243 

"  Cropping  "  leather 41 

"  Cuir  "  color 106 

Currying  and  finishing 218 

Cutch 163 


Dampening  before  rolling 97 

Degras  in  making  stuffing 221 

Dividivi 165 

Domestic  hides  of  the  Eastern,  Middle 

and  Western  States 192 

Draining  after  scrubbing 96 

Drum  wheel  handler 70 

Dry  hides,  table  showing  cost  of  tan- 
ning  243 

Drying  in  the  turret  dryer 97 

saving  in  time  and  labor  and  im- 
proved color  made Ill 

size  of  building  necessary 113 

how  steam  should  be  admitted.  .113 

openings  for  light  and  air 113 

elevator  for  raising  the  leather.  .115 

influence  of  light  and  heat 115 

conveying     leather     from     the 
yard  to  the  drying  lofts 136 


East  India  kips 191 

Elevator  for  raising  leather  to  the 

drying  loft 115 

"  England  "  wheel,  the 73 

Experiment  with  water  and  tan  liquor  63 
in  tanniiig  New  York  City  hides..  85 
in  tanning  by  hydrostatic  pres- 
sure  177 


Ferguson,  Thomas  T.,  experiment  at 
Sparrowbush,  N.  Y.,  on  vacuum 

tanning 179 

Fertilizing  liquids 153 

Flesh  blacking 221 

Fleshing,  cost  of  thorough  work 38 

lime  slaughter  stock 39 

before  liming 40 

sweat  stock 40 

the  German  flesher 41 

Fisk's  whitener  and  buffing  machine .  280 
Furnaces,  directions  for  constructing 

for  burning  wet  tan 224 


Gambier,  or  terra  japonica 162 

its  use  as  a  substitute  for  bark. .  .164 
Gallic  acid,  sole  leather  raised  by  ...  80 

German  flesher,  the 41. 

German  sole  leather £0 

Glue  stock,  saving  and  caring  for  the.  149 

Grain  and  buff  leather 210 

difference    between    that  .made 
from  tanned  leather  and  that 

made  from  green  hide 211 

stamping 212 

strength  of 212 

suggestions  for  manufacture  of.  .213 

Grain,  nature  of  the 103 

great  care  necessary  to  make  it 

perfect 104 

English  custom  of  striking  out 

the ...108 

Grate  surface  necessary   in  wet  tan 

ovens 227 

Grease  on  hides  to  be  removed  by  an 

alkali 30,  91 

how  to  purify  and  cleanse 219 

Green  hides,  table  showing  cost  of 

tanning 243 


Hair,  cattle  and  calves',  saving  the . .  150 
cleansing  and  preparing  for  mar- 
ket   151 

Handling 68 

the  hand  reel 69,  252 

the  rocker  handler 69,  254 

the  drum  wheel  handler 70 

a  method  of  raising  packs 71 

tub  wheel  handler 72 

the  "  England  "  wheel 73 

mechanical  power 74 


INDEX. 


303 


Handling— The  " Cox"  rollers 74 

on  frames 75 

use  of  acid  in 76 

for  upper  and  harness  leather...  83 

Hand  reel,  the 69 

Hanging  hides  in  sweats 27 

Heating  liquors,  pan  for 260 

Heating  surface  necessary  in  wet  tan 

ovens 228 

Hemlock  bark,  a  fair  colored  leather 

from 56,101 

white  and  red 156 

weight  of  a    cord    of    different 

kinds  of 156 

growth  of  in- different  sections  of 

country 158 

Hemlock  leather  made  to  imitate  oak 

leather 107 

Hides,  selection  and  classification. ...  17 
assorting  at  each  stage  of  the  tan- 
ning process 17 

softening  in  soak  and  mill 18 

breaking  the  nerve 19 

kinds  to  be  worked  at  the  same 

time 21 

sweating 23 

hanging  in  sweat  pits 27 

liming 31 

bating 33 

trimming  before  tanning 43 

skinning  the  cheeks  and  throats.  44 

handling  and  plumping 76 

laying  away 84 

experiment  with  N.  Y.  City 85 

cells  of  filled  with  water  and  net 

air 178 

species  and  growth  of 188 

healthy  and  well  grown 188, 

differences  in  at  various  seasons.  189 

climate  and  food,  effect  of  on 189 

Hide  mill,  the 250 

Hide  worker,  Henry  Lampert's 282 

Hook  marks 91 

Howard  leather  washer,  the 95,  264 

How  much  leather  will  a  cord  of  bark 

make 160 

Hydrostatic  pressure,  experiment  in 
tanning  by. 177 


Improved  breeds  of  cattle  make  hides 

thin  and  spready 190 

Instantaneous  combination  of  tannin 
with  gelatine 92 

Insurance,  old  and  new  rates  for  tan- 
neries  138 


Knoederer's  vacuum  tanning  process.181 
Korn,  Charles',  whitener 276 


Laying  away,  time  required  for  sole 

leather -84 

gives  better  color  than  handling.  85 


Laying  away  as  practised  in  Europe..  8f> 

in  Great  Britain 87 

weight  of  liquors  on  last  layer ...  88 

gram  or  flesh  up 91 

Leaches,  round  or  square 126 

construction  of 128 

capacity  of  to  be  proportioned  to 

tannery 122 

brick  and  cement  for  in  England.  133 

Leaching 55 

proper  degree  of  heat  to  be  used.  57 

the  double  leach 58 

the  press  leach 58 

how  it  is  worked 59 

loam  packing  for 60,  119 

construction  of 61 

operation  of. < 62 

number    of    times    bark  is 

washed  with 64 

the  Allen  &  Warren  leach. . .  .65,  260 
concentrated  liquors  obtained  by.  66 

the  McKenzie  leach 66 

revolving  leach 67 

Leather  interest  of  the  United  States 
according  to  the  census  report 

of  1870 245 

Leather  should  be  dry  when  stuffed.  .222 

Leather  splitter,  the  Union 282 

Liming  after  sweating 28 

when  vitriol  is  used 29 

to  unhair 31 

kind  of  lime  to  use 31 

preparation  of  the  limes 31 

old  limes 32 

time  required  for 32 

Prof.  Lufkin's  process 34 

the  "  Buffalo  "  method 35 

handling  in  limes , . .  36 

Liquors,  feeding  hides  with  strong . .  82 
Loam  foundation  desirable  for  tan- 
neries   119 

Loam  packing  for  leaches 60 

Location  of  tanneries 118 

placing  the  buildings  to  reduce 

fire  risks 137 

Loss  of  tannin  in  making  leather 173 

M 

Milling  after  sweating 28 

Morocco  vs.  "pebble  grain"  leather.. 212 
Myrabolams 166 

N 

Nerve,  breaking  of  the,  in  hides  and 

skins 19,  40, 197 


Oak  bark 159 

the  rock  oak,  white  oak,  and  red 

oak 160 

growth  of  oak  trees 161 

Oiling  before  drying 97 

Old  liquors,  acid  in 83 

One  story  'buildings    best  for    tan- 
neries   134 


304 


INDEX. 


Palm  oil  used  by  European  curriers.  .207 

Patents  for  tanning  inventions 176 

Paste 221 

Press  leach,  the 58 

"  Puddling  in"  the  vats 123 


Quick  tanning  process .176 

R 

Reel  for  handling  leather 69,  252 

Refuse  of  tanneries — Utilization  of. .  146 

Rocker  handler,  the 69,  255 

Rollers  for  handlers 74 

Rolling,  proper  condition  of  the  lea- 
ther for 98 

effect  of  the  first 99 

a  second  rolling  necessary 99 

the  American  leather  roller 256 

Rossing  bark 141 

difficulty  of  separating  the  ross . .  142 
will  it  pay  to  ross  bark  for  ex- 
port?  144 

"  Rounding" 43 

Russia  Leather,  original  color  of. 106 


S 


Safety  coupling  for  a  bark  mill 49 

Scouring — the  Lockwood  scourer 268 

the  Fitzhenry  scourer 270 

the  Burdon  scourer 272 

Screen  for  ground  bark 50 

Setting  the  vats  and  leaches 120 

Sheepskins,  effect  of  vitriol  on 79 

Skins — Breaking    of    the    nerve    in 

French  and  German  calfskins.  20 

Selection  before  tanning 20 

Liming 34 

Fine  texture  of  French,  German 

and  Swiss  calfskins 193 

Size  paste 221 

Soap  blacking 221 

Soda  ash,  with  lime,  for  unhairing. . .  35 
Soda  ash  or  sal  soda  for  removing 

white  spots 91 

Softening  hides 18 

Soil  and  climate,  effect  of  on  bark. .  .156 

Sole  leather,  German 80 

Splitting  machine,  the 210 

Sprinkler  leach,  the 65 

Steam  power  to  be  conveyed  by  steam 
in  pipes  rather  than  by  shaft- 
ing  137 

Streams,  "manufacturing"  and  "cu- 
linary"  118 

Strength  of  liquors  for  handling 83 

for  laying  away 84 

for  last  layer 88 

Stuffing  wheel,  the 27 

Sugar  of  lead  and  sulphuric  acid  for 

bleaching  leather 100 

Sulphur,  with  lime  and  soda  ash,  for 

unhairing    35 


Sumac  baths  for  making  a  fair  color.  101 

Sweating,  in  Europe 23 

by  steam 24 

construction  of  cold  sweat  pits. ..  24 
to  control  the  temperature  of  the 

pits 23 

grease  and  salt  on  hides,  stop- 
ping the  action  'of  the  sweat- 
ing process 29 

improved  sweat  pits 24S 

"  Sweet  fern  " 166 


Tan  burning 47,  224 

the  first  practical  success  in 147 

Tanneries,  construction  of. 

Leaches 126 

Framework  and  location  of  build- 
ings  134 

The  turret  dryer Ill 

Plans,  foundations,  etc 117 

Tannin,  difficulty  of  separating  from 

extractive  matter 55 

instantaneous      combination     of 

with  gelatine 92 

Tanning  materials 155 

Tanning,  the  cost  of 169 

in  Europe 174 

Tan  press,  the  Salem 26G 

Tawing  hides  and  skins 188 

Temperature  of  sweat  pits 26 

of  water  in  wheeling  limed  hides.  33 

of  limes 35 

of  water  for  leaching    with  the 

press  leach 57 

of  the  stuffing  wheel 219 

Time  of  tanning  by  Knoederer's  vac- 
uum process 183 

Tools  for  tanners  and  curriers 28(5 

Transferring  packs,  a  method  of 71 

"Trim"  of  leather  adopted  by  Eng- 
lish tanners 42 

Trimming  of  hides 43,  28-L 

Tub  wheel  handler,  the 72 

Turret  dryer,  the 110,  2-3;^ 

U 

Union  whitener  and  buffing  machine, 

the 278 

Union  leather  splitter,  the 282 

Upper  leather  tanned  by  a  cord  of 

bark 170 


Vacuum  tanning 177 

leather  made  "  baggy  "  by 182 

Valonia 165 

Yats  to  rest  on  the  log  conductors. .  ,  121 

"Buffalo," 121 

box 122 

Vegetable  oils  for  currying 207 

Vitriol,  the  use  of  lime  on  hides  raised 

by 28 

its  use  in  Great  Britain 29 

its  employment  in  handling 7o 


305 


INDEX. 


Vitriol — Difficulty     in     determining 

how  much' to  use 78 

should  not    be  used    on    sweat 
stock 79 

W 

Warm  water  to  be  used  in  soaking 

hard  hides 18 

Washing  after  coming  from  the  laya- 
ways 94 


Water  in  cells  of  hides 178 

Wheel  scrubbing 95 

Wheel  stuffing 219 

Whitener,  Charles  Korn's 270 

the  Union 278 

Fisk's 280 

White  spots  in  sole  leather 89 

Wilcox,Pa.,  cost  of  wet  tan  furnace 

at 240 

Working  hides  and  skins  to  break  the 

nerve 40 


APPENDIX, 


REPORT 


OP 


SKEETL,  C.  E., 


ON  THE 


COMPARATIVE  ECONOMIES 

OF 

BURNING  WET  SPENT  TAN 

BY 

THE  VARIOUS  DETACHED  FURNACES  NOW  IN  USE 

BY  THE  TANNERS  OF  PENNSYLVANIA 

AND  NEW  YORK, 


NEW  YORK  : 

OFFICE  OF  THE  SHOE  AND  LEATHER  REPORTER. 

17  SPRUCE  STREET. 

1876. 


BURNING  WET  TAN  IN  DETACHED  FURNACES. 

In  order  to  explain  and  justify  the  great  particularity  with  which  this  series  of  experi- 
ments have  been  conducted,  it  is  proper  to  say  that  in  the  suit  of  Black  vs.  Thorne,  in 
which  was  involved  the  merits  of  the  so-called  Thompson  patent  for  burning  wet  tan 
bark,  saw  dust,  &c.,  both  Profs.  Silliman  and  Thutston  insisted  upon  the  theoretical 
and  practical  superiority  of  the  Thompson  furnace  over  tbose  in  public  use  at  the  time 
of  this  patent.  Prof.  Thurston  was  compelled  to  admit,  however,  that  methods  outside 
of  the  Thompson  patent  were  quite  successful,  and  gave  practically  all  the  power  re- 
quired, but  thought,  from  his  observation  and  experiments  at  two  tanneries,  that  the 
Thompson  furnace  would  give  about  thirty  per  cent,  better  results  from  a  given  amount 
of  wet  spent  tan  than  the  furnaces  outside  of  the  patent. 

As  this  result  was  known  by  all  practical  tanners  not  to  be  true,  they  naturally  felt 
anxious  to  have  the  experiments  made  with  more  care  than  Prof.  Thurston  had  pre- 
tended to  exercise.  He  guessed  and  estimated  too  much,  and  weighed  and  measured 
too  little,  to  carry  the  conviction  of  his  theories,  as  against  the  known  results  in  actual 
practice.  Hence  it  was  that  J.  B.  Hoyt  and  J.  S.  Schultz,  representing  the  tanners, 
sought  for  some  expert  that  should  carefully  retry  the  experiments  so  imperfectly  per- 
formed by  Prof.  Thurston,  and  they  were  greatly  aided  in  this  endeavor  by  Mr.  B.  F. 
Isharwood,  Chief  Engineer  of  the  U.  S.  Navy.  The  letter  received  from  him  so  fully  sots 
forth  the  grounds  of  his  commendation  that  it  is  here  inserted  with  the  correspondence 
and  report  which  follows. 


NEW  YOKK,  August  17,  1875,  111  East  36th  Street. 

DEAB  SIB  : — I  take  the  liberty  to  write  you  in  regard  to  some  experiments  which  I 
understand  you  contemplate,  and  which  I  hope  you  will  have  made,  on  the  evaporative 
efficiency  of  wet  tan  bark  burned  in  the  furnace  of  a  steam  boiler.  The  subject  is  one 
of  great  interest  in  engineering,  which  is  my  apology  for  thus  troubling  you;  and  tbe 
problem  should  be  solved  in  so  complete  and  appropriate  a  manner  as  to  remove  for- 
ever the  doubts  now  resting  on  it. 

In  my  opinion  there  is  no  person  of  my  acquaintance  so  thoroughly  qualified  to  con- 
duct such  experiments,  and  ascertain  their  results,  as  Mr.  Theron  Skeel.  He  has  all 
the  necessary  qualifications  of  an  education,  both  mathenntical  and  practical,  andheis 
an  expert  experimentalist.  He  is  thoroughly  versed  in  the  subject,  and  his  report  will 
command  a  respect  and  confidence  not  easy  to  obtain  for  that  of  any  other.  Whatever 
experiments  Mr.  Skeel  makes  will  be  devised  in  a  manner  to  defy  hypercriticism  as  to 
the  propriety  of  their  results,  and  his  literary  ability  will  enable  'him  to  present  them 
so  clearly,  forcibly  and  full  that  they  will  be  understood  and  accepted  by  all. 

Should  you  conclude  to  have  these  experiments  made,  I  volunteer  the  advice  that  you 
allow  Mr.  Skeel  to  have  full  power  in  devising  and  conducting  them.  By  so  doing  I  "am 
confident  you  will  obtain  such  results,  and  in  such  a  manner,  as  will  forever  settle  the 
questions  at  issue.  The  worst  extravagance  will  be  to  so  limit  the  experiments  as  to  cause 
the  least  shadow  of  doubt  to  remain.  I  hope,  in  the  interest  of  industrial  science,  that 
you  will  furnish  Mr.  Skeel  the  means  to  do  justice  to  both  himself  and  the  subject. 
Your  obedient  servant,  B.  F.  ISHERWOOD, 

JACKSON  S.  SCHULTZ.  Chief  Engineer  II.  S.  Navy. 


NEW  YORK,  Aug.  20,  1875. 
MB.  THEBON  SKEEL: 

My  Dear  Sir:— Within  a  few  days  I  have  received  a  letter  from  B.  F.  Isherwood,  Esq., 
Chief  Engineer  of  the  U.  S.  Navy,  in  which  he  recommends  you  as  a  suitable  person 
to  test  the  evaporating  power  of  wet  tan  bark  when  burned  in  furnaces  in  the  front  of 
steam  boilers. 

In  view  of  your  conceded  ability,  in  common  with  other  tanners  who  are  interested 
in  the  subject  above  referred  to,  and  particularly  as  developed  by  the  controversy 
arising  out  of  the  suit  now  pending  on  the  Thompson  patent  for  burning  wet  fuels,  we 
desire  that  you  at  once  proceed  to  test,  by  a  series  of  experiments  at  several  tanneries, 
the  comparative  merits  of  the  various  methods,  but  p  rticularly  those  of  Thompson, 
Hoyt,  Crockett,  and  other  such  modifications  of  these  as  in  your  judgment  mav  tend  to 
throw  light  upon  the  general  subject  embraced  in  the  "consumption  of  wet  fuels  in 
detached  furnaces  or  ovens." 

*********** 

Our  wish  and  instructions  to  you  are,  that  you  make  your  tests  in  the  most  thorough 
manner,  and,  when  you  have  finished  your  work,  that  you  report  to  us  m  writing. 

Very  truly, 
(Signed)  J.  S.  SCHULTZ,  ou  behclf  of  J.  B.  Hoyt  and  others. 


REPORT. 


86  TRYING  PLACE,  NEW  YORK,  Dec.  30,  1875. 

JACKSON  S.  SCHULTZ,  Esq.,  Nos.  63  and  65  Cliff'  Street,  New  York, 
J.  B.  HOYT,  Esq.,  and  otliers  : 

GENTLEMEN — I  submit  the  following  report  of  the  experiments 
made  in  accordance  with  your  letter  of  instructions  preceding. 

The  experiments  were  made  on  three  forms  of  furnaces  de- 
signed to  burn  spent  tan  in  the  condition  in  which  it  comes  from 
the  leaches.  The  object  of  the  experiments  was  to  determine  in 
which  kind  of  furnace  the  hot  gas  developed  by  the  burning  of  a 
given  quantity  of  wet  tan  would  evaporate  the  most  water  in  the 
boilers  attached.  The  furnace  which  excels  in  this  respect  may 
be  said  to  be  the  most  economical  of  bark. 

This  must  be  distinguished  from  commercial  economy,  which 
depends  upon  the  value  in  money  of  the  spent  tan,  the  cost  of 
the  furnace  and  of  attendance  and  repairs.  In  the  present  state 
of  the  art  about  one-half  of  the  spent  tan  is  thrown  away  in  all 
sole  leather  tanneries,  for  they  only  use  about  one-half  of  all  the 
tan  made  to  make  the  steam  necessary  for  the  whole  tannery. 
Under  these  circumstances  the  moiety  of  the  tan  has  no  value  in 
any  case,  and  in  some  locations  is  worse  than  valueless,  for 
the  tanners  are  prohibited  by  law  from  dumping  the  tan  into  the 
stream,  or  where  there  is  no  stream  to  dump  it  into  (as  is  some- 
times the  case),  they  are  obliged  to  either  carfc  it  away  or  to  erect 
an  additional  furnace  especially  to  burn  it.  The  term  economy 
as  used  in  this  paper  refers  to  economy  in  the  use  of  bark  only. 

The  economy  of  any  furnace  (the  term  furnace  including  the 


d 

whole   combination   of  ovens   and  boilsrs)   evidently  depends 
upon  : 

1.  The  total  heat  which  would  be  developed  by  the  perfect 
combustion  of  the  quantity  of  tan  fed  into  the  oven. 

2.  The  portion  of  the  heat  that  is  developed  by  the  combus- 
tion that  takes  place  in  the  furnace. 

3.  The  portion  of  the  heat  developed  which  is  utilized  by  the 
boilers. 

The  first  condition  depends  entirely  upon  the  bark,  and  is  in- 
dependent of  the  oven  or  boiler.*  The  second  condition  depends 
almost  entirely  upon  the  oven  and  is  independent  of  the  boiler. 
The  third  condition  depends  both  upon  the  furnace  and  boiler. 

In  order  that  any  set  of  experiments  should  be  conclusive  in 
themselves  without  reference  to  any  conditions  but  the  quantity 
of  tan  burned  and  of  water  evaporated,  it  is  necessary  that  a  set 
of  ovens  should  be  built  of  each  kind  and  connected  to  exactly 
similar  boilers,  and  that  these  ovens  shall  be  fed  at  the  same 
time  with  the  same  quantity  of  tan  from  the  same  leach,,  and  that 
the  pressure  of  steam  and  the  temperature  of  the  feed  water 
shall  be  the  same  in  each  case.  Such  experiments  would  be 
comparative,  but  are  not  practicable.  In  the  absence  of  exactly 
similar  conditions,  it  is  necessary  to  consider  (so  far  as  we  are 
able)  all  the  variations. 

The  experiments  described  in  this  report  were  made  in  1875 
as  follows  : 

Sept.  22 — Crockett  furnace,  Stevens'  tannery,  Great  Bend,  N.  Y. 

Sept.  24— Crockett  furnace,  Wells'  "  Southport "  tannery,  Webb's  Mills,  N.  Y. 

Sept.  26— Thompson  furnace,  H.  F.  Inderlied,  Brackneyville,  N.  Y. 

Sept.  29 — Thompson  furnace,  Weed's  tannery,  Binghamton,  N.  Y. 

Oct.  6— Crockett  furnace,  Wells'  "  Southport "  tannery,  Webb's  Mills,  N.  Y. 

Oct.  16-17— Hoyt's  furnace,  Wilcox  Tanning  Co.,  Wilcox,  Pa. 

Dec.  9— Crockett  furnace,  Wells'  "  Southport  "  tannery,  Webb's  Mills,  N.  Y. 

Dec.  10— Crockett  furnace,  Weils'  "  Southport "  tannery,  Webb's  Mills,  N.  Y. 

The  plans  and  dimensions  of  the  ovens  and  boilers  and  the 
detailed  description  of  the  experiments  are  given  in  the  appen- 
dices to  this  report. 

FUEL. 

,The  fuel  was  in  all  cases  spent  bark  of  hemlock  trees,  called 
"  tan."  Ihe  trees  are  felled  while  living  and  stripped  of  their 
bark  during  the  summer  season.  The  bark  is  piled  up  in  the 

*If  the  tan  were  so  thoroughly  leached  and  dried  as  to  be  fed  into  the  furnace  nearly 
in  the  condition  of  perjectty  dry  wood  it  is  probable  that  the  combustion  would  be  mor« 
nearly  perfect,  with  the  same  supply  of  air,  than  if  the  same  furnace  were  fed  with  im- 
perfectly leached  bark. 

(j 


ff 

woods  after  being  stripped,  and  during  the  winter  hauled  into 
the  tannery  and  piled  up  again  until  needed  for  use. 

The  bark  is  peeled  from  all  sizes  of  hemlock  trees  down  to  about 
6  inches  in  diameter,  the  largest  being  about  30  and  the  average 
perhaps  15  in  diameter.  Good  average  hemlock  land  will  peel 
about  12  cords  of  bark  to  the  acre.  One  man  will  fell,  peel  and 
pile  about  1J  cords  of  bark  per  day. 

The  bark  when  originally  peeled  from  the  trees,  at  the  same 
season,  has  probably  nearly  the  same  composition  in  all  locali- 
ties. This  has  been  found  to  be  true  of  wood,  and  therefore 
inferentially  of  bark.  In  that  condition,  then,  a  given  weight  of 
bark  would  probably  correspond  to  a  given  quantity  of  heat  in 
all  cases.  If,  however,  it  is  not  burned  at  once,  it  dries  more  or 
less  according  to  the  length  of  time  and  the  circumstances  under 
which  it  is  stored.  The  time  of  storing  varies  in  practice  from  a 
few  weeks  to  several  years,  and  while  sometimes  it  is  stored  in 
large  piles  and  exposed  to  the  weather,  at  others  it  is  stored  in 
small  piles  under  sheds.  After  being  stored  a  certain  length 
of  time  it  loses  all  the  water  except  about  14  to  16  per 
cent.,  leaving  the  balance  containing  84  to  86  parts  of 
dry  wood  and  14  to  16  parts  of  water.*  If  more  thor- 
oughly dried  than  this  by  exposure  in  a  hot  kiln,  it  will  on 
exposure  to  the  atmosphere  reabsoib  an  amount  of  water  vary- 
ing from  14  to  16  per  cent,  with  the  hygrometric  condition  of 
the  air.  Dry  wood,  in  the  sense  used  in  this  paper,  is  under- 
stood to  be  wood  that  has  parted  with  all  the  water  it  will  when 
exposed  to  dry  air  at  a  temperature  of  110°  Centigrade  or  230° 
Fahrenheit. 

The  unit  of  measure  of  the  bark  in  this  condition  (before 
being  ground,)  called  "  chip  bark,"  is  among  tanners  the  cord, 
being  a  pile  of  bark  8  feet  long  by  4  feet  wide  by  4  feet  high. 
The  weight  of  this  volume  of  bark  is  variously  estimated  at 
from  1,800  to  2,240  pounds,  and  probably  varies  within  these 
limits  with  the  manner  of  packing  and  the  weight  of  water 
contained. 

Before  leaching  the  bark  is  ground  in  a  machine  called  a  "  bark 
mill."  The  bark  in  its  original  condition  consists  of  an  outer 
shell  of  hard  dry  substance,  analogous  to  "  cori,"  and  an  inner 

*I  am  informed  by  a  gentleman  who  has  had  considerable  experience  in  drying  wood 
for  manufacture  into  spools  that  Rreen  wood  if  cut  into  fagpots  and  exposed  to  the  air 
in  eheds  protected  from  the  weather,  would  lose  in  one  year  all  the  water  it  contained 
except  about  15  per  cent.,  as  compared  with  kiln  dried  wood  at  150  deg.  F,  The  kiln 
dried  wood  would  reabsorb  this  15  per  cent,  when  exposed  to  the  air. 


layer  of  a  substance  containing  more  sap  and  more  like  woody 
fiber.  In  the  first  process  of  grinding  the  outer  shell  grinds 
much  finer  than  the  inner.  In  some  tanneries  the  whole  product 
from  the  mill  is  sifted  in  a  revolving  screen,  and  the  coarser  part, 
consisting  mainly  of  the  large  pieces  from  the  inner  layer,  is  sent 
back  to  the  mill  and  reground. 

The  weight  of  a  cord  of  ground  unleached  tan  (being  deter- 
mined by  weighing  the  contents  of  several  boxes  containing 
exactly  25  cubic  feet  each)  the  bark  being  shoveled  into  the 
box,  not  packed,  and  struck  off  with  a  straight  edge,  was  found 
to  be  at  the  various  tanneries  as  follows  : 

Wells' 2,582  pounds 

Brackneyville 2,353  pounds 

Wilcox  (fine) 2,418  pounds 

Wilcox  (coarse) . .  .2,284  pounds 

Average .- 2,351  pounds 

The  water  contained  in  the  last  two  specimens  as  comp  ared 
with  the  same  dried  at  110°  C.  was  found  to  be  : 

Wilcox  (fine) 18.1  per  cent 

Wilcox  (coarse) 17.0  per  cent 

And  therefore  the  weight  of  a  cord  of  dry  ground  unleached 
bark: 

Wilcox  (fine) 1,980  pounds 

Wilcox  (coarse) 1,895  pounds 

Average 1,938  pounds 

But  at  Wilcox  all  coarse  ground  tan  is  sent  back  to  the  mill 
and  reground,  and  therefore  the  weight  of  a  cord  of  fresh  ground 
bark  will  be  the  mean  of  the  coarse  and  the  fine,  or  2,418 
pounds,  the  percentage  of  water  contained  17^,  and  the  weight 
of  the  cord  of  dry  bark  1,995  pounds. 

Probably  no  sensible  error  will  arise  if  we  assume  for  all  cases 
the  weight  of  a 

Cord  of  dry  unleacbed  ground  bark  =  2.000  pounds. 

In  this  condition  probably  the  same  weight  of  bark  will  de- 
yelop  the  same  amount  of  heat  in  all  localities,  and  within  the 
limits  of  practice  the  same  is  true  of  equal  volumes. 

After  being  ground  the  bark  is  "  leached,"  that  is,  placed  in  a 
wooden  leach  having  a  perforated  bottom  and  saturated  with  warm 
water  for  several  days.  This  water  percolates  through  the  bark 
and  carries  off  with  it,  if  the  process  is  continued  long  enough, 
all  soluble  matter. 

After  the  soluble  matter  is  supposed  to  be  all  out,  the  water 
is  allowed  to  drain  off  and  the  residue,  called  "  wet  spent  tan," 


is  shoveled  out  of  the  leaches  and  carried  to  the  furnace  to  be 
burned. 

A  cord  of  the  bark  in  this  condition  has  been  in  former  experi- 
ments taken  as  a  unit  of  measure  of  the  amount  of  heat  equiva- 
lent to  the  tan  fed  into  the  furnace.  In  order  to  test  the 
accuracy  of  this  assumption  the  whole  quantity  of  tan  burned  in 
each  experiment  was  measured  and  weighed,  as  in  case  of  dry 
bark,  by  shoveling  it  into  a  box  containing  about  |  cord,  striking 
off  with  a  straight  edge,  and  weighing  the  contents. 

The  weight  of  a  cord  of  wet  leached  tan  under  these  circum- 
stances was  found  to  be  at  various  tanneries  as  follows : 

Stevens' 4,442  pounds 

Wells'  (U 4,294  pounds 

Wells'    (3) 4,275  pounds 

Weed's 4  270  pounds 

Welle5  (4) 4,260  pounds 

Wells'  (2) 4,225  pounds 

Brackneyville 4,112  pounds 

Wilcox 4,076  pounds 

Average 4,244  pounds 

The  per  centage  of  water  lost  by  drying*  at  110°  C.  was  found 
to  be  at  the  various  tanneries  : 

Wells' 63.4 

Wells'  (2) 62.8 

Wells' (4; 62.3 

Wells'  (3) 61.5 

Stevens' 61.5 

Wilcox 61.2 

Brackneyville 59.0 

Weed's 55.1 

*The  average  composition  of  bark  dried  at  80  deg.  C.  is  given  by  M.  Violet ; 

Carbon 48. 6 

Hydrogen 6.8 

Oxygen 41 .8 

Ash 8.3 

100 

If  this  bark  had  been  dried  at  110  deg.  C.,  as  was  done  in  the  experiments,  its  composi- 
tion would  have  been  changed  by  the  loss  of  5  per  cent,  of  water,  and  would  have  been : 

Carbon 51.2 

Hydrogen 7.0 

Oxygen 89.8 

Ash 8.5 

100~ 

Or  of  51.2  per  cent,  carbon,  1.2  per  cent,  hydrogen,  44.2  per  cent,  of  hydrogen  and 
oxygen  in  the  proportion  to  form  water,  and  3.5  per  cent.  ash. 

The  weight  of  the  water  which  one  pound  of  the  bark  in  thig  condition  would  evapo- 
rate from  212  deg.  F.,  computed  by  allowing  15  pounds  per  pound  of  carbon  and  64 
pounds  per  pound  of  hydrogen,  will  be  : 

Carbon      51.2@15  =  7.68 
Hydrogen  1.2@64  =  0.77 

145 
Of  this  55-100  of  pound  of  water  are  latent  in  gas,  leaving  available  hett  7  9-10 


And  consequently  the  weight  of  the  dry  portion  of  the  cord  : 

Weed's 1,917 

Wilcox 1,582 

Wells'  (4) 1,606 

Wells'  t'3) 1,646 

Brackneyville 1,686 

Stevens' 1.710 

Wells'  (1) 1,572 

Wells'  (2) 1,572 

Average 1,661 

Average  weight,  rejecting  Weed's 1,625 

In  order  to  try  the  effect  of  packing  on  the  weight  of  the  cord, 
several  boxes  were  weighed  containing  tan  packed  by  a  man 
(weighing  at  "Wells'  about  150  pounds,  and  at  Brackneyville  180 
pounds)  stamping  it  down  as  fast  as  shoveled  in,  the  top  being 
struck  ©ff  with  a  straight  edge  as  before.  The  weight  of  the  cord 
was  as  follows  : 

Wells' 5,327 

Brackneyville 5,490 

Average 5,405 

The  per  cent,  of  water  contained  being  as  before,  the  weight 
of  the  dry  portion  will  be  : 

Wells' 1,950 

Brackneyville 2,251 

Average 2,100 

At  Wilcox  the  whole  contents  of  two  leaches  were  weighed. 
The  weight  of  a  cord  at  the  density  of  packing  in  the  leach  was 
found  to  be  : 

Wilcox 5,219       y 

And  the  weight  of  the  dry  portion  : 

Wilcox 2,025 

In  the  experiment  marked  Wells'  (3)  and  Wells'  (4),  the  tan 
was  used  during  the  first  part  of  the  day  from  the  bottom  of  one 
leach  and  during  the  second  part  from  the  top  of  another.  The 
following  exhibits  the  weight  of  a  cord  taken  from  various  parts 

pounds  from  212  deg.  Probably  no  sensible  error  will  arise  if  the  thermal  equivalent  of 
one  pound  of  bark  dried  at  110  deg.  C.  is  taken  at  8%  pounds  of  water  evaporated  from 
212  deg.  P. 

The  thermal  equivalent  oi  a  coid  should  1  e  in  water  evapoiated  from  212  deg  : 

2,000X8.5=17.000  pounds. 

Prof.  Johnson  has  made  some  experiments  on  dry  pine  wood  giving  7%  pounds  of 
water  from  212  deg.  F.  No  estimate  of  the  water  contained  is  given,  but  assuming  it  to 
have  been  20  per  cent,  (and  it  could  not  have  been  less),  thtre  results  from  his  ex- 
periment : 

Pounds  of  water  evaporated  from  212  deg.  F.  by  pound  of  pine  wood  (dry) 9.98 

In  his  experiment,  1  36-100  pound  of  water  were  latent  in  gas,  leaving  available 
heat,  8.02. 


f 

of  the  leach,  the  whole  capacity  being  10  cords,  the  bottom  cord 
being  called  the  10th  : 

1st  day,    8th  cord  in  leach,  48  hours  draining,  weight 4,262  pounds 

1st  day,  10th  cord  in  leach,  56  hours  draining,  weight 4,306  pounds 

2d  day,  1st  cord  in  leach,  24  hours  draining,  weight 4,262  pounds 

2d  day,  2d  cord  in  leach,  32  hours  draining,  weight 4,211  pounds 

2d  day,  3d  cord  in  leach,  38  hours  draining,  weight 4  257  pounds 

2d  day,  4th  cord  in  leach,  44  hours  draining,  weight 4,290  pounds 

A  sample  of  bark  to  determine  water  was  not  kept  separately 
for  each  cord.  The  weight  of  a  wet  cord  seems  steadily  to  increase 
from  the  top  toward  the  bottom,  but  not  very  rapidly,  the  whole 
increase  being  less  than  2  per  cent.  The  masses  of  bark  were 
broken  up  by  shoveling  out  of  the  leach,  and  were  all  measured 
at  the  same  density,  these  figures  having  no  reference  to  the 
tightness  of  packing  iu  various  parts  of  the  leach. 

The  extreme  variations  of  weight  of  the  dry  portions,  from 
1,917  at  Weed's  to  1,572  at  Wells',  would  at  first  seem  to  point 
to  an  error  in  measurement.  The  following  exhibits  the 
difference : 

Wells'.  Weed's. 

Weight  of  cord  of  wet  tan 4,294  4.270 

Weight  of  dry  portion 1,572  1,917— difference  345,  Weed's  most 

Water 2,722  2,353— difference  369,  Welles'  most 

*The  dry  green  bark,  having  the  same  composition  in  both 
cases,  is,  according  to  M.  Violet,  made  up  of  : 

1.  Of  a  material  called  cellulose,  which  has  always  the  same 
composition. 

2.  Of  an  incrusting  material  which  is  richer  in  carbon  and 
hydrogen,   and  of  which  the    principal  constituents  are   resin, 
gum,  starch,  sugar,  glucose  and  tannin. 

3.  Of  mineral  matter  or  ash. 

The  soluble  constituents  are  wholly  or  partially  extracted, 
according  as  the  process  of  leaching  is  more  or  less  complete. 
It  is  possible,  then,  that  the  soluble  portion  was  nearly  all  ex- 
tracted from  the  Wells'  bark  and  but  partially  extracted  from 
the  Weed's  bark,  the  pores  being  filled  with  water  in  both  cases, 
but  there  being  more  empty  pores  to  contain  water  in  Welles' 
bark. 

If  this  should  be  true,  the  balance  of  the  soluble  matter  may 
be  extracted  by  thorough  leaching,  and  the  dry  portion  remain- 
ing should  have  been  nearly  the  same  weight  in  every  case. 

In  order  to  test  this  theory  a  given  weight  of  wet  bark  was 
taken,  the  sample  from  each  tannery  boiled  for  2J  hours,  the 


*Annales  de  Chimio  and  de  Physique,  vols.  xxm.  and  ixxn. 


liquor  filtered,  and  the  balance  dried  at  110°  C.  as  before.     The 
result  of  this  experiment  was  as  follows  : 

Orieinal  weight  of  Loss  of  weight  by  Final  weight  of 

dry  cord  from  boiling  2%  leached  dry 

leach.  hours.  cord. 

Stevens 1,710  pounds  84  pounds  1,626  pounds 

Brackneyville 1,649  pounds  113  pounds  1,536  pounds 

Weed's 1,917  pounds  408  pounds  1,509  pounds 

Wells'  (1) 1,572  pounds  93  pounds  L479  pounds 

Wilcox 1,582  pounds  98  pounds  1.484  pounds 

Wells1  (2) 1,572  pounds  148  pounds  1,424  pounds 

Average 1,667  157  1,510 

The  variations  of  the  weight  of  the  dry  boiled  portion  may  be 
due  in  part  to  the  fact  that  the  soluble  matter  is  not  yet  all  out, 
for  they  were  only  all  boiled  the  same  time,  and  not  until  they 
ceased  to  lose,  as  would  have  been  the  final  test.  Enough,  how- 
ever, was  done  to  show  that  so  far  as  the  extremes  are  concerned, 
Weed  and  Wilcox,  the  measurements  are  probably  correct. 

A  specimen  of  the  unleached  bark  from  Wilcox's  was  soaked 
in  cold  water  for  36  hours  and  boiled  for  6  hours,  the  liquor 
filtered,  and  the  residue  dried  at  110°  C.  as  before  : 

Original  weight  of  Loss  ofw<  ight  Final  weight  of 
cord    dry    un-      by    leaching      cord  boiled 
leached  bark.       and  boi  ing.          dry  bark. 

Wilcox  (fine) 1,980  341  1,639 

Wilcox  (coarse) 1,895  366  1,529 

Average 1,937  354  1,589 

Screened  and  reground  bark  at  Wilcox 1,995  365  1,630 

This  bark  would  probably  have  lost  more  if  the  process  of 
leaching  had  been  continued  for  six  days,  as  in  practice,  in  place 
of  42  hours. 

Probably  no  sensible  error  will  arise  if  the  weight  of  a  cord  of 
thoroughly  leached  bark  from  the  tannery  be  taken  at  1,400 
pounds,  when  dried  at  110°  C. 

It  appears,  then,  from  these  experiments  that  the  average 
weights  are  as  follows  ; 

Cord  of  average  green  Cord  of  well  leached  wet 

'ground  bark.  bark  from  tannery. 

Soluble  matter 500  pounds    20  per  cent  000  pouuda    00.    per  cent 

Insoluble   matter 1,500  pounds    60  per  cent  1,500  pounds    35.7  per  cent 

Water 500  pounds    20  per  cent  2,700  pounds    6*.3  per  cent 

2,500  pounds  100  per  cent  4,200  pounds  100     per  cent 

The  experiments  do  not  show  what  the  500  pounds  of  extract- 
ive matter  consists  of,  but  only  that  it  is  material  soluble  in  hot 
and  cold  water. 

The  proportion  of  water  does  not  increase  with  the  size  of  the 
lumps,  as  was  found  by  drying  a  specimen  of  very  large  lumps 


ti 


from  cord.  The  water  contained  was  shown  to  be  exactly  the 
same  as  in  the  fine. 

A  cord  of  tan  thoroughly  leached  and  saturated  with  water 
weighs  more  and  contains  more  water  than  a  cord  imperfectly 
leached.* 

A  cord  of  fine  ground  tan  weighs  more  than  a  cord  of  coarse 
ground,  as  a  barrel  of  meal  weighs  more  than  a  barrel  of  corn. 

THE  CROCKETT  FURNACE. 

The  Crockett  furnaces  experimented  upon  consist  of  an  oven 
of  fire  brick,  constructed  near  the  boiler,  and  haying  a  set  of 
cone  grate  bars  of  cast  iron.  The  tan  is  fed  in  through  doors  in 
the  front. 

The  depth  of  the  furnace  is  limited,  as  in  the  ordinary  furnace 
for  coal,  by  the  distance  to  which  the  fireman  can  easily  throw 
the  tan,  to  6J  feet,  but  may  be  as  wide  as  is  necessary 
to  give  the  grate  surface,  and  varies  in  practice  from  6  to  12 
feet  in  width. 

The  fire  is  started  (as  in  every  case)  with  dry  wood,  and  con- 
tinually replenished  until  the  brick  work  is  hot,  after  which  no 
more  wood  is  necessary.  The  frequency  of  feeding  depends 
upon  the  rapidity  of  consumption.  When  burning  at  the  rate  of 
7  pounds  of  dry  tan  per  square  foot  of  grate  per  hour,  each  por- 
tion of  the  furnace  requires  to  be  fed  with  fresh  tan  every  three- 
quarters  of  an  hour  at  least.  If  there  are  several  doors,  each  door 
has  to  be  opened  every  three-quarters  of  an  hour.  At  Welles* 
furnace  there  were  three  doors,  and  some  door  was  opened  every 
15  minutes.  The  time  of  feeding  under  these  circumstances  was 
about  1J  minutes,  so  that  the  doors  were  open  one-tenth  of  the 
time.  If  the  fuel  burned  regularly  over  the  grate,  the  feeding 
could  be  less  frequent. 

The  crown  of  the  furnace  is  a  segmental  or  elliptical  arch,  and 
the  distance  from  the  crown  to  the  grate  varies  from  1J  to  2J 
feet  in  different  ovens.  The  fire  bridge  is  at  the  back  of  the 
grate,  and  is  a  continuation  of  the  back  vertical  wall  of  the  ash 

*The  specific  gravity  of  the  material  extracted  from  the  bark  is  nearly  1%  times  that 
of  water,  so  that  the  500  pounds  of  material  extracted  would  be  replaced  by  330  pounds 

of  water.    The  weight  would  be  as  follows: 

Before  leaching    After  leaching 

Soluble  matter 500  

Solid  matter 1,500  1,500 

Water  mechanically  held  between  particles 2;250  2,250 

Water  in  pores  originally  filled  with  soluble  matter 330 

Weight  of  cord  of  wet  tan 4,250  4,080 

These  are  nearly  the  weights  of  cord  at  Wilcox  and  Weed's. 


13 


pit.  It  rises  about  1J  feet  above  the  grate,  and  extends  entirely 
across  the  oven.  The  arch  over  the  oven  is  generally  from  2  to  3 
feet  longer  than  the  grate,  and  forms  the  support  for  the  front 
end  of  the  boilers. 

The  boilers  are  generally  horizontal  flue  boilers,  with  two  flues  ; 
the  products  of  combustion,  after  leaving  the  furnace,  passing 
forward  under  the  boilers,  returning  through  the  flues,  and  finally 
passing  in  front  to  the  chimney  through  a  sheet  iron  connection. 
The  chimney  is  generally  of  sheet  iron,  and  is  sometimes  set 
directly  over  the  boilers,  and  sometimes  carried  on  a  brick 
foundation. 

The  main  difficulty  in  keeping  a  uniform  fire  is  the  compara- 
tively small  weight  of  fuel  in  the  furnace  at  one  time.  If  the 
fire  is  earned  on  an  average  9  inches  thick,  there  will  only  be  in 
the  furnace  at  one  time  (if  the  grate  is  6J  feet  long  by  12  feet 
wide)  800  pounds  of  combustible.  At  the  rapid  rate  these  fur- 
naces are  generally  fired,  being,  in  the  case  of  Wells'  (1),  800 
pounds  dry  tan  per  hour,  this  would  only  last  one  hour.  A  fur- 
nace burning  coal  at  the  rate  of  10  pounds  per  square  foot  per 
hour  would  contain  coal  enough  to  last  6  hours.  The  conditions 
of  a  tan  bark  fire,  then,  in  the  Crockett  furnace,  fed  every  hour, 
may  be  imagined  by  supposing  a  coal  fire  fed  every  six  hours. 
STEVENS'  FURNACE  AT  GREAT  BEND. 

The  performance  of  this  furnace  during  the  experiment  indi- 
cates the  economy  of  the  Crockett  furnace  when  forced  to  the 
utmost.  During  the  experiment  the  number  of  pounds  of  dry 
tan  burned  per  hour  was  : 

Per  square  foot  of  grate  surface  ......................................  10.70 

Per  square  foot  of  heating  surface  ...................................     1.61 

Per  square  foot  of  the  cross  area  of  flues  ............................  258  00 

In  order  to  consume  this  tan  the  damper  and  ash  pit  doors 
were  kept  wide  open  and  the  furnace  fired  every  ten  minutes. 

The  method  of  firing  was  first  to  fill  the  holes  that  had  burned 
through,  and  then  to  cover  the  whole  surface  with  a  layer  of  tan 
about  3  inches  thick. 

The  tan  thrown  in  first  forms  a  uniform  layer  over  the  surface. 
It  appears  to  undergo  a  species  of  distillation,  during  which  the 
water  is  evaporated,  the  tan  maintaining  its  original  brown  color. 

Just  before  firing,  the  furnace  was  a  dull  red  over  about  half  its 
surface,  the  color  fading  out  into  a  black  toward  the  front,  and  the 
surface  of  the  tan  was  burned  through  into  holes  wherever  the  origi- 
nal tan  was  thinnest  or  the  fire  hottest,  but  mostly  where  the  grate 
had  broken  away  and  left  large  crevasses  through  which  the  tan  fell 


11 

*v ___ 

into  the  ash  pit.  At  the  instant  before  firing,  the  temperature  of 
the  gases  leaving  the  furnace  was  scarcely  sufficient  to  melt  silver, 
and  there  was  no  smoke  coming  from  the  chimney,  but  occasion- 
ally a  few  sparks. 

The  fireman  would  now  throw  in  as  described  the  charge  of 
about  300  pounds  of  wet  tan  through  both  doors  alternately. 

Immediately  on  closing  the  doors  the  destructive  distillation  of 
the  tan  commenced,  under  the  combined  influence  of  the  heat 
radiated  from  the  surface  of  the  arch  above  and  of  the  hot  embers 
on  the  grate  beneath.  By  looking  in  through  some  of  the  crevasses 
in  the  front  of  the  furnace  hundreds  of  little  jets  of  white  smoke 
could  be  seen  issuing  from  the  whole  surface  of  the  tan. 

During  the  process  of  distillation,  which  lasted  about  3  minutes, 
the  smoke  and  steam  which  was  unable  to  find  an  outlet  into  the 
chimney  issued  in  small  quantities  through  the  crevasses  in  the 
brick  work  into  the  fire  room,  or  was  forced  back  through  the  grate 
into  tbe  ash  pit.  A  careful  examination  of  the  edges  of  the 
crevasses  in  the  brick  work  showed  them  to  be  covered  with  a 
deposit  of  an  oily  substance,  undoubtedly  condensed  from  the 
smoke,  showing  that  at  this  time  the  combustion  was  imperfect, 
and  that  the  smoke  issuing  from  them  had  contained  combustible 
matter.  During  the  process  of  most  rapid  distillation,  no  air 
entering  the  ash  pit,  combustion  must  have  been  entirely  suspended, 
and  whatever  gases  were  generated  must  have  passed  away  un- 
consumed.  Toward  the  end  the  crown  of  the  furnace  becomes 
black  all  over,  owing  no  doubt  to  the  heat  absorbed  by  the  water 
in  the  tan. 

Now  there  are  signs  of  combustion  commencing.  These  are, 
first,  the  cessation  of  the  smoke  from  the  crevasses  into  the  fire- 
room,  and  little  jets  of  yellow  flame  replacing  the  smoke  in  the 
furnace.  They  begin  gradually,  and  in  about  two  minutes  cover 
the  whole  surface  of  the  tan,  which  gradually  grows  red  hot  and 
consumes.  From  the  time  of  the  first  appearance  of  the  flame, 
the  crown  of  the  furnace  gradually  grows  hotter,  and  just  before 
firing  is  red  hot  over  half  its  surface  as  before. 

The  appearance  of  the  smoke  during  the  first  part  of  the  cycle 
indicates  the  presence  of  combustible  gas  at  that  time.  Unfortu- 
nately, the  loss  of  heat  by  combustible  gas  does  not  cease  when 
the  flame  commences,  for  although  at  that  time  some  of  the  gas  is 
consumed,  probably  a  large  part  of  it,  forced  from  the  tan  by  the 
heat  of  the  embers  below,  and  issuing  into  a  comparatively  cool 
oven,  does  not  acquire  sufficient  temperature  to  consume,  even 


11 


though  mixed  with  sufficient  air.  I  consider  that  in  the  Stevens 
.  furnace,  fired  in  this  way,  probably  the  whole  effect  of  the  gaseous 
portion  of  the  fuel  (about  25  per  cent.)  was  lost. 

This  loss  was  aggravated  by  the  very  thin  layer  in  which  the 
bark  was  spread  over  the  whole  surface,  allowing  all  the  water  to 
be  evaporated  in  a  few  minutes,  the  volume  of  gas  completely 
filling  all  egress  from  the  boilers,  thus  arresting  combustion  and 
allowing  the  furnace  to  cool  down  below  the  temperature  necessary 
for  the  ignition  of  the  gases  expelled  during  the  subsequent 
process. 

This  loss  would  have  been  probably  almost  entirely  prevented 
by  closing  the  ash  pit  down  so  as  to  bum  about  half  as  much  tan, 
or  by  putting  in  two  more  boilers,  so  as  to  have  twice  as  much 
area  of  flue.  In  either  case  the  effect  would  be  to  give  an  excess 
of  area  to  the  outlet  over  the  inlet  of  the  oven,  so  that  the  com- 
bustion need  not  cease  while  the  distillation  is  taking  place,  in 
which  case  the  temperature  of  the  oven  would  be  maintained 
nearly  constant,  and  the  gas  consumed  as  fast  as  expelled. 

It  is  also  necessary  for  the  combustion  of  the  gas  that  there 
should  be  supplied  an  amount  of  air  that  does  not  pass  through 
the  incandescent  tan  on  the  grate.  Unless  this  air  is  supplied  the 
gas  will  pass  off  unconsumed. 

This  air  is  supplied  practically  by  the  holes  burned  in  the  fire. 
The  tan,  after  being  dried  in  the  furnace,  commences  to  bum  away 
most  rapidly  where  tan  is  thinnest  or  the  draft  strongest.  The 
layers  of  bark  around  this  hole  do  not  slide  down  and  fill  it,  but 
stand  perfectly  perpendicular,  or  even  overhang  a  little.  These 
holes  generally  form  on  the  crest  of  the  grate  bars,  and  in  a  few 
minutes  enlarge  rapidly,  and  finally  lay  bare  the  whole  crest. 
They  act  a  very  efficient  and  beneficial  part  if  not  allowed  to  in- 
crease too  much,  but  check  the  fire  and  cool  the  oven  if  left  too 
long  without  being  filled. 

A  description  of  the  performance  of  a  Crockett  furnace,  when 
these  holes  were  in  one  experiment  allowed  to  form,  and  in  an- 
other when  they  were  kept  from  forming  by  filling  up  all  hollows 
with  fresh  tan  before  the  surface  had  burned  away  (marked  Wells' 
3  and  Wells'  2),  in  which  it  appeared  that  with  the  same  rate  of 
combustion,  and  with  the  same  temperature  in  the  oven,  the  per- 
formance of  the  furnace  in  the  case  where  the  holes  were  kept 
open  exceeded  the  performance  when  the  holes  were  kept  shut  by 
more  than  25  per  cent. 

In  the  case  of  the  Stevens  furnace  at  Great  Bend,  the  main 


& 


15 


cause  of  the  failure  in  economy  was  undoubtedly  owing  to  the 
high  rate  of  combustion  at  which  it  was  forced. 

CROCKETT  FURNACE  AT  WELLS'  TANNERY. 

This  furnace  was  similar  to  the  Stevens  furnace,  except  that 
there  were  3  boilers,  each  42  inches  in  diameter  and  22  feet  6  inches 
long,  with  two  horizontal  flues,  13  inches  internal  diameter.  The 
grate  was  6  feet  6  inches  deep  by  12  feet  wide. 

The  boilers  had  been  in  use  for  22  years  and  were  said  to  be 
covered  with  scales  on  the  inside  and  the  brick  work  was  full  of 
fissures.  There  were  many  leaks  around  the  sheet  iron  work  con- 
necting the  boilers  with  the  stack  and  in  the  back  connection. 

The  oven  was  new  and  in  good  order.  It  had  been  recently 
built  to  replace  a  Thompson  oven  torn  down,  being  connected 
with  the  same  boilers.  The  grates  were  "  cone  grates,"  and  were 
new  and  in  good  order. 

In  the  first  experiment,  marked  "  Wells'  (1),"  the  furnace  was 
tested  in  the  ceiidition  it  was  found,  the  rate  of  combustion  being 
a  little  more  than  enough  to  supply  the  steam  necessary  to  run  the 
tannery. 

In  the  second  experiment,  marked  "  Wells'  (2),"  the  air  leaks  in 
stone  work  and  sheet  iron  work  were  closed,  as  far  as  practicable, 
with  mortar,  and  the  rate  of  combustion  was  reduced  to  the  same 
as  at  "  Weed's,"  being  nearly  64-100  pounds  of  dry  tan  per  square 
foot  of  heating  surface  per  hour.  All  the  holes  in  the  fire  were 
filled,  as  soon  as  they  commenced  to  develop,  with  a  shovel  full  of 
wet  tan. 

In  the  third  experiment  the  same  pains  were  taken  to  stop  air 
leaks,  same  rate  of  combustion  was  maintained,  only  holes  were 
allowed  to  form  in  fire,  and  the  top  of  the  oven  was  covered  with 
wet  tan,  which  was  afterward  burned  as  in  the  furnaces  fed  from 
the  top. 

In  the  fourth  experiment  same  conditions  were  maintained  as  in 
last,  except  that  cross  section  of  flues  were  reduced  to  2-J  square 
feet, 

EXPERIMENT  MARKED  "  WELLS'  (1)." 

The  performance  of  the  furnace  during  this  experiment  indicates 
the  effect  of  forcing  a  Crockett  furnace  beyond  its  capacity,  the 
rate  of  combustion  being  in  pounds  of  dry  tan  per  hour  : 

Per  square  foot  of  heating  surface 0.98 

Per  square  foot  of  grate  surface 10.50 

Per  square  foot  of  cross  section  of  fl  ies 147.00 

Being  more  than  50  per  cent,  in  excess'of  the  rate  necessary  to 
allow  perfect  combustion. 


16 


The  performance  was  injured  by  the  cold  air  which  leaked  into 
the  flues  through  fissures  in  brick  work,  and  particularly  by  the 
cold  air  which  had  leaked  into  the  chimney  by  the  opening  in  the 
sheet  iron  work  around  front  connection.  An  opening  was  found 
here  after  experiment  was  concluded  exposing  36  square  inches. 
The  temperature  of  the  gas  leaving  the  flues,  taken  in  chimney 
beyond  this  opening,  was  580°,  or  270°  hotter  than  the  steam, 
while  at  Wilcox,  at  nearly  the  same  rate  of  combustion,  where 
there  was  no  leak,  the  temperature  of  the  gas  700°,  or  380°  hotter 
than  the  steam.  The  inference  would  be  that  the  temperature  of 
the  gas  at  Wells'  (1)  would  have  been  680°  if  no  cold  air  had 
leaked  into  flue  between  the  boiler  and  the  thermometer.  The 
proportion  of  air  necessary  to  reduce  the  temperature  100°  would 
be  16|  per  cent.  The  weight  of  air  found  in  the  chimney  was  21  6-10 
pounds  per  pound  of  dry  tan  by  chemical  analysis,  and,  therefore, 
the  air  that  passed  through  the  flues  was  18  pounds  per  pound  of 
dry  tan. 

The  air  passing  through  the  fire  was  still  less  than  this  by  an 
amount  that  leaked  into  the  flues  en  route  from  the  furnace  to  the 
chimney. 

The  furnace  was  fed  about  every  10  minutes  through  one  door 
at  a  time,  thus  making  the  weight  of  a  charge  about  300  pounds  of 
wet  tan,  the  balance  of  the  hourly  consumption  being  thrown  in, 
in  occasional  shovel's  full,  to  fill  up  holes. 

No  care  was  taken  ts  fill  up  holes  burned  in  fire.  These  were  so 
large,  just  before  feeding,  as  to  expose  about  one  square  foot  of 
opening  for  passage  of  cold  air  from  ash  pit  through  holes  in  grate 
bars.  The  temperature  of  the  gases  leaving  the  furnace,  as  indi- 
cated by  a  piece  of  metal  on  the  bridge  wall,  was  just  sufficient  to 
melt  silver  at  their  hottest.  This  occurred  about  midway  in  the 
interval  of  time  between  the  feeding  and  the  burning  down  of  the 
fire  ready  to  be  fed  again.  The  surface  of  the  arch  over  the  fur- 
nace showed  at  this  time  a  bright  red  over  about  half  its  surface, 
fading  out  toward  the  front.  As  the  holes  developed  in  the  fire, 
the  color  died  away,  and  was  a  dull  red  just  before  feeding.  After 
feeding  the  color  faded  away  and  was  invisible  for  a  few  minutes, 
gradually  recovering  to  a  bright  red  just  before  feeding  again. 
The  extremes  of  temperature  of  the  furnace  were  then  probably 
1,000°  and  1,900°,  and  the  average  about  1,500°,  corresponding  to 
about  15  pounds  air  per  pound  dry  tan. 

The  general  appearance  of  the  furnace  was  as  at  Stevens',  only 
less  exaggerated.  The  period  during  which  the  tan  was  not  burn- 


17 


ing  was  shorter,  and  the  smoke  was  never  returned  into  the  fire 
room. 

The  large  supply  of  air  was  probably  mostly  due  to  the  holes 
allowed  to  burn  in  the  fire.  Probably  a  considerable  portion  of 
the  combustible  gas  was  wasted  in  this  experiment.  The  heat 
unaccounted  for  in  the  gas,  water  and  steam  was  0.40  pounds  of 
water  evaporated  from  212°,  or  about  5  per  cent. 

EXPERIMENT  MARKED  WELLS'  (2). 

After  the  completion  of  the  [experiment  marked  Wells'  (1),  and 
noticing  the  injurious  effects  of  the  holes  burned  in  the  fire,  it  was 
determined  to  try  the  effect  of  keeping  the  holes  entirely  closed, 
and  at  the  same  time  to  reduce  the  rate  of  combustion  to  that  at 
Weed's. 

The  outside  of  the  boiler  was  carefully  covered  with  mortar  to 
prevent  any  air  leaking  into  the  flues.  The  only  air  that  did  leak 
in  was  probably  between  the  boilers  and  the  chimney  and  had  no 
effect  on  the  economy. 

The  surface  of  the  fire  was  carefully  watched,  and  as  soon  as  a 
hole  began  to  develop  it  was  closed  by  opening  the  furnace  door 
and  throwing  as  quickly  as  possible  a  shovel  full  of  tan  directly 
into  it. 

The  furnace  was  divided  into  three  sections,  corresponding  to 
the  three  doors,  and  these  sections  were  fired  every  hour,  the 
weight  of  the  charge  being  400  pounds  of  wet  tan,  the  balance  of 
the  hourly  consumption  being  used  to  fill  up  holes.  The  fire  was 
kept  about  one  foot  thick.  The  temperature  of  the  furnace  was 
higher  than  during  the  previous  experiment,  and  nearly  the  same 
as  in  the  succeeding  experiment,  indicating  a  smaller  supply  of  air. 
As  no  air  could  reach  the  chamber  in  which  the  gases  were  gene- 
rated without  first  passing  through  the  12  inches  of  tan,  there 
could  but  very  little  free  air  reach  them  at  all,  and  they  probably 
passed  away  entirely  unconsumed,  entailing  a  loss  upon  the  fur- 
nace of  about  25  per  cent.  The  steam  formed  was  only  three- 
fourths  of  that  in  the  succeeding  experiment,  or  indicating  a  loss 
of  20  per  cent. 

EXPERIMENT  MARKED  WELLS'  (3). 

The  results  of  this  experiment  probably  are  the  maximum  for 
this  furnace  in  the  condition  which  it  now  is. 

The  rate  of  combustion  was  the  same  as  in  last  experiment,  and 
the  air  leaks  were  carefully  stopped,  except  those  in  the  sheet  iron 
work  between  the  boiler  and  the  chimney.  The  furnace  was  fired 
about  every  15  minutes,  the  weight  of  the  charge  being  about  300 


18 

^ 

"\ 

pounds  of  wet  tan,  the  balance  of  the  hourly  consumption  being 
scattered  in  as  the  fire  seemed  to  need  it. 

The  temperature  of  the  furnace  was  more  nearly  uniform,  being 
at  the  highest  sufficient  to  easily  melt  silver,  and  at  the  lowest  a 
dull  red,  or  about  1,200°  and  1,900°,  and  the  mean  temperature  of 
not  less  than  1,650°.  I  estimated  the  mean  temperature  from  the 
comparative  time  the  highest  and  lowest  lasted. 

The  average  opening  of  the  furnace  doors  during  the  hour  was 
about  7  minutes.  The  area  exposed  by  the  open  furnace  door  for 
the  inflow  of  air  was  about  300  square  inches,  while  the  average 
opening  of  the  ash  pit  doors  was  about  100  square  inches,  or 
about  one-third.  It  appears  then  that  the  furnace  doors  would 
have  passed  into  the  furnace  3  times  as  much  air  as  the  ash  pit 
doors  while  they  were  open,  but  as  the  furnace  doors  would  only 
be  open  about  7  minutes  during  the  hour,  would  only  admit  about 
30  per  cent,  of  the  air  admitted  through  the  ash  pit.  The  tempera- 
ture of  the  fire  when  the  doors  were  closed  being  as  high  as  in  any 
furnace  tested,  shows  that  at  that  time  the  tan  was  burning  with 
as  small  a  supply  of  air  as  in  any  case,  or  10  pounds  per  pound 
dry  tan. 

The  weight  of  air  per  pound  of  dry  tan,  as  determined  by 
velocity  of  smoke,  was  16  pounds.  A  considerable  portion  of  this 
must  have  leaked  in  through  the  opening  in  the  sheet  iron  work. 

The  temperature  of  the  furnace  is  computed  from  heat  : 

Given  up  by  products  of  combustion  to  steam,  taking  weight  of  air  per  pound 

of  dry  tan  at  16  pounds,  and  adding  temperature  of  chimney,  490  degrees 1,310° 

From  the  thermal  equivalent  of  tan,  allowing  0.25  pound  for  radiation,  and 
assuming  products  of  combustion  to  take  all  heat,  the  supply  of  air  being 
16  pounds  per  pound  dry  tan 1,300° 

But  the  mean  temperature  of  furnace  was  found  to  be  1,650°, 
indicating  that  25  per  cent,  of  the  air  in  the  flues  had  not  passed 
through  the  furnace,  leaving  the  supply  of  air  12  pounds  per 
pound  of  dry  tan. 

In  this  experiment  the  draft  was  controlled  by  nearly  closing 
the  ash  pit  doors.  No  smoke  came  from  the  chimney.  The  top 
of  oven  was  covered  with  tan. 

This  was  the  most  successful  experiment  made  on  the  Crockett 
furnace,  and  the  results  indicate  that  the  success  was  mainly 
owing  to  the  manner  of  firing,  and  to  the  fact  the  draft  was  con- 
trolled by  the  ash  pit  doors,  in  place  of  by  the  damper  in  the 
chimney,  the  effect  being  to  make  the  area  of  egress  larger  than 
the  area  entrance  for  the  air.  The  tan  on  the  top  of  the  furnace 
undoubtedly  saved  some  heat.  This  experiment  being  the  best 


19 


performance  of  the  Crockett,  should  be  compared  with  the  best 
performance  of  the  Hoyt  and  Thompson  furnaces  at  Wilcox  and 
Binghamton.  If  the  air  in  the  chimney  had  not  been  diluted  with 
25  per  cent,  of  air  from  the  outside,  its  temperature  would  have 
been  650°. 

EXPERIMENT  MARKED  WELLS'  (4). 

This  experiment  was  made  to  determine  the  effect  of  reducing 
area  of  exit  for  gas.  The  rate  of  combustion  was  the  same,  the 
manner  of  firing  was  the  same,  the  temperature  of  the  furnace 
was  nearly  the  same,  and  the  chimney  10°  colder. 

Notwithstanding,  the  steam  generated  by  one  pound  of  dry  tan 
was  5  per  cent.  less.  The  area  of  flues  in  this  experiment  was 
reduced  until  they  had  some  influence  on  the  gas  flowing  from  the 
boiler,  and  resulted  in  a  small  loss  of  combustible  gas.  There  was 
some  smoke  during  this  exeriment. 

During  the  experiment  marked  Wells'  (1)  there  was  an  excess 
of  steam  formed  over  that  required  to  run  tannery. 

During  the  experiment  marked  Wells'  (3)  there  was  sufficient 
steam  formed  to  carry  60  pounds  pressure  and  run  the  whole  tan- 
nerry,  including  heating  liquors  and  all  the  machinery  they  ever 
ran.  The  consumption  of  tan  was  at  the  rate  of  4  cords  in  12 
hours,  or,  allowing  1  cord  for  banking  fires,  5  cords  per  day,  being 
less  than  one-half  of  the  bark  they  used  for  tanning  their  hides. 

MANNEE  OF  MAKING  EXPERIMENTS. 

The  experiments  were  all  made  in  the  same  general  manner  as 
follows  : 

Tan — The  tan  was  measured  in  a  box  at  its  natural  density ; 
that  is,  merely  shoveled  into  the  box  and  "struck"  with  a 
straight  edge.  The  box  was  counterbalanced  on  platform 
scales,  and  the  weight  of  tan  contained  in  each  box  noted  in 
the  log.  After  the  furnace  had  been  running  a  few  hours, 
so  that  the  amount  of  tan  required  was  known,  it  was 
arranged  to  deliver  a  boxful  every  5,  10,  15  or  20  minutes, 
according  as  required.  The  boxes,  under  these  circumstances, 
were  dumped  at  exactly  the  end  of  these  intervals ;  that  is,  if  there 
were  required  3  boxes  of  tan  per  hour,  one  would  be  dumped 
at  the  even  hour,  one  at  20  minutes  past,  and  one  at  20  minutes 
before,  exactly.  The  object  of  this  arrangement  was  to  prevent 
any  confusion  as  to  the  number  of  boxes  delivered.  When,  as  at 
Wilcox,  there  are  used  sometimes  20  boxes  an  hour,  such  an  ar- 
rangement is  found  to  be  necessary.  The  tally  of  the  weight  of 
each  box,  and  the  minute  at  which  it  was  dumped,  was  kept  by 


myself  and  the  man  who  was  in  charge  of  the  gang  of  shovelers. 

Water  in  tan — The  water  in  the  tan  was  determined  by  drying 
several  specimens  of  200  grammes  each,  taken  from  a  sample  of 
one  quart  brought  from  the  tannery  in  a  hermetically  sealed  glass 
jar.  The  tan  was  dried  by  my  associate,  Prof.  J.  K.  Eees,  of 
Columbia  College,  in  an  air  bath  at  110°  Centigrade.  The  method 
of  obtaining  the  sample  of  one  quart  was  as  follows  :  There  was 
provided  a  tin  case  with  a  lid  and  lock.  A  double  handful  of  tan 
was  taken  from  each  boxful  of  tan  as  weighed  upon  the  scale  and 
thrown  into  the  tin  case.  The  case  was  kept  locked  except  when 
opened  to  receive  samples.  At  the  end  of  the  day  there  would  be 
collected  in  this  case  from  40  to  200  double  handfuls  of  tan,  leing 
collected  in  equal  portions  from  every  boxful  of  tan  used. 

At  -the  end  of  the  day  the  tan  in  the  case  was  shaken  well  up 
and  then  spread  out  upon  a  table  and  divided  into  equal  small 
parts,  alternate  small  parts  being  taken  and  the  balance  rejected. 
The  original  easeful  was  thus  reduced  by  successive  divisions  (one 
half  being  rejected  each  time)  to  one  quart,  when  it  was  carefully 
placed  in  the  jar,  sealed,  labeled,  and  sent  to  New  York  by 
express. 

Water — The  water  pumped  into  the  boiler  was  all  measured  in 
casks,  the  weight  contained  by  the  casks,  weighed  on  the  same 
scale  as  the  tan,  having  been  originally  determined.  There  were 
generally  three  tiers  of  casks,  the  lower  one  being  connected  with 
the  pumps  and  acting  as  a  reservoir,  the  middle  one  acting  as  a 
measuring  cask,  and  the  upper  one  receiving  the  supply  of  water 
and  being  provided  with  an  overflow  at  the  top  and  a  plug  in  the 
bottom.  The  middle  or  measuring  cask  also  had  a  hole  in  the 
bottom  and  a  plug. 

The  mode  of  operation  was  as  follows  :  The  man  in  charge  of 
the  water  would,  when  the  measuring  cask  was  empty,  put  the 
plug  in  the  bottom  and  pull  out  the  plug  from  the  upper  barrel,  the 
water  immediately  commencing  to  flow  from  the  upper  into  the 
measuring  cask.  When  the  measuring  cask  was  full,  he  would  put 
the  plug  in  the  upper  barrel,  and  after  a  few  seconds,  when  the 
surface  of  the  water  had  subsided  to  the  level  of  the  overflow  hole, 
would  pull  out  the  plug  in  the  measuring  barrel  and  allow  the 
water  to  flow  into  the  lower  barrel,  whence  it  would  be  pumped 
into  the  boilers.  The  same  precaution  was  taken  to  avoid  con- 
fusion by  emptying  barrels  at  exactly  even  intervals,  as  in  weigh- 
ing tan. 

Water  entrained  with  steam — This  was  determined  by  a  special 


31 

w 

w 

apparatus  designed  for  the  purpose  and  carried  around  to  all  the 
tanneries  tested.  It  consisted  of  a  worm,  through  which  a  small 
portion  of  the  steam  coming  from  the  boiler  was  passed,  exposed 
to  cold  water  on  the  outside.  The  measurements  taken  were  : 

1.  The  weight  of  water  coming  from  worm  per  hour  being  the 
sum  of  the  steam  and  water  coming  from  the  boiler  into  the  worm. 

2.  The  weight  of  water  passing  over  the  outside  of  the  worm, 
which  carried  away  all  the  heat  abstracted  from  the  water  and 
steam. 

3.  The  temperature  of  the  water  before  and  after  passing  the 
worm,  the  temperature  of  the  water  delivered  from  the  worm,  and 
the  pressure  of  the  steam  in  the  boiler. 

These  three  measurements  supply  all  the  data  necessary  to 
determine  the  amount  of  water  entrained  with  the  steam. 

The  weight  of  water  passing  the  outside  of  the  worm  was  determ- 
ined by  noticing  the  head  of  water  over  an  orifice  in  the  bottom 
of  the  box  in  which  the  worm  was,  necessary  to  force  all  the  water 
through.  The  volume  of  water  which  would  be  delivered  by  this 
orifice  for  each  J  inch  increment  of  head  had  been  previously 
determined,  and  was  as  follows  : 

CUBIC  FEET  OF  WATER  DELIVERED  PER  HOUR  FROM  OBIFICE  IN  BOTTOM  OF  TANK  AT  VABIOUS 
HEADS  FROM  16  INCHES  TO  25  INCHES,  AT  A  TEMPERATURE  OP  72  DEGREES  F. 

Head.  Cubic  feet  water.  Head.  Cubic  feet  water. 

25      inches 39.60  20%  inches 35.47 

24%  inches 22  20      inches 26 

24%  inches 02  19%  inches    05 

24%  inches 88.82  19%  inches 34.82 

24     inches 6t  19%  inches 59 

23%  inches 42  19      inches 36 

23%  inches 22  18%  inches 13 

23%  inches 01  18%  inches 33.90 

23      inches 37.80  18%  inches .68 

22%  inches 60  18      inches 45 

22%  inches 39  17%  inches 21 

22%  inches 18  17%  inches 32.98 

22      inches 36.98  17%  inches 74 

21%  inches 77  17      inches 50 

21%  inches 55  16%  inches 26 

21%  inches 34  16%  inches 02 

21      inches 13  16%  inches 31.78 

20%  inches 35.91  16     inches 53 

20%  inches 69 

The  figure  given  in  the  log  is  the  "  head  of  water  in  tank."  By 
entering  this  table  with  the  head,  the  volume  of  water  correspond- 
ing can  be  determined.* 

*It  is  believed  that  the  idea  of  determining  the  water  entrained  with  the  steam  by 
condensing  a  small  portion  continuously  in  a  worm  and  weighing  and  measuring  all 
quantities,  originated  with  Mr.  J.  D.  Van  Buren,  Jr. 


Temperatures — The  temperatures,  when  below  600°,  were  taken 
by  a  thermometer.  Above  600°,  they  had  to  be  approximated  to 
by  means  of  the  melting  point  of  metals.  Specimens  of  the 
same  piece  of  metal  were  used  at  all  furnaces,  and  the  results  are 
therefore  fairly  comparative. 

Method  of  proceeding — The  engineer  generally  took  charge  of 
the  firing,  and  conducted  it  in  the  manner  he  supposed  best  cal- 
culated to  produce  the  best  result.  As  all  of  the  engineers  seemed 
to  feel  considerable  pride  in  having  their  furnaces  do  well,  I  have 
reason  to  suppose  each  did  his  best. 

Supervision — I  was  present  at  the  furnace  during  the  whole  of 
each  experiment,  never  leaving  it  for  a  single  instant,  and  had  a 
complete  supervision  of  all  operations  during  the  whole  time. 

Ashes  and  refuse — These  were  determined  by  raking  out  the 
fire  and  commencing  with  the  tan  that  had  been  weighed  (in 
Stevens'  and  Wells'  1),  and  by  weighing  the  ashes  and  refuse  dry 
at  the  end  of  experiment.  The  ashes  were  found  to  be  so  small  a 
percentage,  and  so  much  mixed  with  unconsumed  tan,  that  the 
attempt  to  measure  them  was  given  up  after  these  experiments. 

In  ah1  others  the  fire  was  left  at  same  condition  at  end  as  be- 
ginning, i.  e.,  Thompson  and  Wilcox  furnaces  full,  and  Crockett 
average  thickness. 

THOMPSON  FURNACES. 

These  furnaces  are  built  in  some  respects  as  described  in  the 
patents  of  Moses  Thompson,  as  interpreted  by  the  court.  They 
consist  of  a  series  of  ovens  arranged  in  pairs,  each  pair  of  ovens 
with  the  boilers  attached  being  complete  in  itself.  The  ovens  are 
built  of  fire-brick,  generally  from  4  to  4J  feet  in  diameter  and 
from  10  to  12  feet  long.  The  crowns  of  the  ovens  are  semicircular, 
and  the  grates  are  in  the  horizontal  diameter. 

The  ovens  are  fed  with  wet  tan  through  two  openings  in 
the  top  of  each  oven.  These  openings  are  about  one  foot  in 
diameter,  and  so  placed  in  the  top  of  the  oven  as  to  best  distribute 
the  tan  uniformly  over  the  grate.  They  are  supplied  with  iron 
covers,  but  except  when  starting  or  burning  down  the  fires  these 
covers  are  not  used,  as  the  tan,  kept  two  feet  deep  all  over  the  fire 
room  floor,  effectually  seals  these  openings.  The  tan  is  fed  as 
often  as  in  the  judgment  of  the  fireman  it  is  required. 

When  about  to  feed,  he  first  breaks  down  the  layers  of  bark 
which  have  dried  and  baked  hard  over  the  top  and  in  the  feed 
hole,  and  then  with  a  bar  spreads  out  the  mass  of  embers  and 
ashes  left  from  the  tan  last  fed  in,  and  finally  shovels  into  the 


|V£^ 

r 


oven  all  the  bark  that  will  run  into  the  feed  holes,  and  ends  by 
filling  all  up  and  tramping  down  the  bark  into  the  hole,  and  covers 
the  top  with  about  two  feet  of  wet  tan  as  before. 

So  far  as  in  the  method  of  construction  and  operation,  I  do  not 
understand  that  the  representatives  of  Thompson  make  any  claims 
to  novelty. 

Their  peculiar  claims  are  as  follows  : 

The  grates  are  made  of  fire  brick  and  are  2J  inches  wide  on  top 
and  have  a  space  between  them  ^  inch  wide,  the  total  area  of 
openings  between  the  bars  for  the  admission  of  air  being  less  than 
20  per  cent,  of  the  total  grate  surface,  while  in  the  ordinary  forms 
of  grate  for  coal  it  is  about  33  per  cent.  «i 

The  space  between  the  bars  (£  inch  wide)  allows  a  small  amount 
of  tan  to  run  through,  partly  from  its  own  weight,  during  the 
whole  process  of  combustion,  but  mostly  while  the  fire  is  being 
stirred  preparatory  to  being  fed.  The  whole  amount  that  runs 
through  is,  however,  a  very  inconsiderable  proportion,  and  would 
scarcely  be  felt  if  it  were  lost.  I  do  not  think  it  can  exceed  10 
per  cent,  in  either  of  the  furnaces  experimented  on,  and  was 
probably  much  less.  The  amount  that  runs  through,  to  a  certain 
extent,  regulates  itself.  It  falls  into  a  second  oven,  built  of  fire 
brick,  taking  the  place  of  the  ordinary  ash  pit.  This  oven  is 
double  for  each  furnace,  the  dividing  wall  being  necessary  to  sup- 
port the  fire  brick  grates.  In  the  furnace  at  Binghamton  they 
were  each  22  inches  wide  and  12  feet  long.  All  the  air  that  enters 
the  oven  through  the  grate  passes  through  a  small  register  in  the 
ash  pit  door  into  the  ash  pit,  and  may  then  rise  through  the  grate 
into  the  furnace,  or  may  pass  along  under  the  grate  over  the  glow- 
ing surface  of  the  embers  in  the  ash  pit.  The  amount  of  air  reach- 
ing the  embers  in  the  back  end  of  the  ash  pit  is  necessarily  small. 
The  embers  falling  through  the  grate  slowly  accumulate  in  the 
ash  pit,  not  consuming  as  fast  as  they  pass  through,  until  the  top 
of  the  pile  of  embers  touches  the  bottom  of  the  grate  bar  and  pre- 
vents the  falling  through  of  any  more.  During  the  time  the  embers 
are  accumulating  they  only  fall  through  very  slowly,  perhaps  two 
or  three  a  second. 

When  the  embers  are  accumulated  in  the  ash  pit  nearly  up  to 
the  grate  bars,  the  whole  surface  of  the  mass  of  embers,  brick 
work  and  grate  bars  has  a  very  high  temperature,  perhaps  2,000°  F. 
The  reason  for  this  is,  I  conceive,  not  on  account  of  the  quantity 
of  tan  consumed  there,  or  on  account  of  the  perfection  of  the 
combustion,  but  because  the  heat  radiated  from  the  embers  is  not 


M 


carried  away.  Only  a  very  small  quantity  of  air  circulates 
through  the  ash  pit  under  these  circumstances,  and  as  all  the  ash 
pits  in  the  group,  except  the  two  outside  ones,  are  surrounded  by 
others  equally  hot,  but  little  heat  is  lost  by  radiation. 

When,  on  the  other  hand,  the  surface  of  the  embers  is  six  or 
eight  inches  below  the  under  side  of  the  grate  bars,  the  tempera- 
ture of  the  gas  at  the  back  end,  after  passing  over  the  whole 
length  of  the  ash  pit,  is  not  sufficient  to  melt  lead. 

The  other  peculiarity  of  the  Thompson  furnace,  as  built  at 
Binghamton  or  Brackneyville,  is  the  contraction  and  combination 
of  the  outlets  for  the  products  of  combustion  from  each  pair  of 
ovens. 

The  inventor  claims  that  by  contracting  and  combining  the  flues 
leading  from  the  furnace  to  the  boiler,  any  combustible  gas  coming 
from  one  furnace  will  be  consumed  by  the  excess  of  oxygen  in  the 
products  of  combustion  coming  from  the  other,  or,  in  the  words  of 
Prof.  Silliman,  "the  gases  from  the  two  furnaces  may  mingle 
and  consume  each  other." 

In  order  that  this  may  take  place  these  three  conditions  must 
simultaneously  exist  : 

1.  There  must  be  combustible  gas  in  the  products  of  combus- 
tion of  one  furnace. 

2.  There  must  be  an  excess  of  oxygen  in  the  products  of  com- 
bustion of  the  other. 

3.  There  must  be  a  sufficiently  high  temperature  in  the  mixed 
gas  (about  1,500°). 

There  was  no  provision  for  the  admission  of  air  into  the  com- 
bustion chamber  of  either  the  Thompson  furnace  at  Binghamton 
or  Brackneyville  other  than  that  which  found  its  way  through  the 
oven  without  uniting  with  the  incandescent  tan  —  that  is,  that 
passed  through  an  oven  10  feet  long  filled  with  tan  at  a  tempera- 
ture of  nearly  2,000°.  If  there  were  any  combustion  taking  place 
in  this  chamber  I  judge  there  must  have  been  some  appearance  of 
flame  there.  There  was  a  small  hole  drilled  in  the  door  of  the 
chamber  of  the  furnace  at  Binghamton  (Weed's)  which  allowed  an 
observation  of  the  whole  interior  at  any  time  without  opening  the 
door.  The  whole  interior  was  nearly  always  perfectly  clear. 
Occasionally  a  little  flame  came  out  of  the  oven  info  the  chamber. 

WEED'S  FURNACE  AT  BINGHAMTON. 

The  experiment  was  made  on  this  furnace  by  allowing  the  engi- 
neer to  take  entire  charge  of  the  method  and  quantity  of  firing,  he 


proceeding  as  lie  said  lie  had  found  by  long  experience  to  be  the 
best  way. 

The  tan  was  brought  from  the  leaches  and  dumped  on  the  fire 
room  floor,  where  it  was  kept  about  two  feet  thick  the  whole  time. 

The  fireman  fired  the  oven  without  any  apparent  system,  the 
average  number  of  times  each  oven  was  fired  being,  including  both 
holes,  twice  every  3  hours  or  8  times  during  a  day  of  12  hours. 
Sometimes  both  feed  holes  were  fed  at  once  in  one  furnace  of  the 
pair,  sometimes  one  feed  hole  in  each  was  fed,  and  sometimes  both 
feed  holes  in  each  furnace  during  the  same  hour,  but  generally  one 
feed  hole  in  one  oven  in  one  hour  and  the  opposite  feed  hole  in 
the  next  oven  during  the  next  hour,  the  feed  holes  nearest  the 
boiler  being  fed  every  four  hours,  and  those  'farthest  from  the 
boiler  every  two  hours. 

The  ash  pit  doors  were  arranged  so  as  to  expose  an  area  of 
nearly  one-third  square  foot  for  each  oven,  or  one-sixth  square  foot 
for  each  ash  pit,  and  were  not  changed  during  the  experiment. 
One  ash  pit  was  raked  out  partly,  the  other  being  nearly  full  of 
incandescent  embers. 

There  was  scarcely  any  smoke  issuing  at  any  time  from  the 
chimney,  it  being  just  perceptible  occasionally. 

The  rate  of  combustion  remained  nearly  constant  during  the 
whole  day,  and  was  nearly  65-100  pounds  of  dry  tan  per  hour 
per  square  foot  of  heating  surface. 

The  tan  on  being  fed  through  the  feed  holes  into  the  oven  imme- 
diately commenced  to  give  off  vapor  from  its  surface,  and,  as  soon  as 
the  immediate  surface  was  dried,  to  undergo  a  species  of  destructive 
distillation  giving  off  combustible  gas.  This  gas  accumulated  in 
the  furnace  apparently  faster  than  it  was  carried  away,  for  the 
smoke  would,  just  after  firing,  return  into  the  fire  room  through 
the  tan  packed  into  the  upper  part  of  the  feed  hole.  The  fire 
room  was  continually  full  of  smoke.  Part  of  this  came  from  the 
combustion  of  the  tan  when  heaped  around  the  sheet  iron  work  of 
the  front  connection,  and  part  of  it  from  the  destructive  distilla- 
tion of  the  wet  tan  on  the  top  of  the  ovens,  the  lower  layers  being 
found  perfectly  charred,  but  I  am  of  the  opinion  that  part  came 
from  the  oven  back  into  the  fire  room. 

The  gas  from  the  furnace,  after  passing  into  the  combustion 
chamber,  passed  forward  under  the  boilers  and  returned  through 
the  tubes  into  a  sheet  iron  front  connection,  thence  into  the 
stack.  The  boilers  were  unprotected  on  top  and  had  steam 
drums. 


The  tan  on  being  fed  into  the  furnace  immediately  spread  out 
into  a  cone,  the  angle  at  the  vertex  being  nearly  90  degrees, 
reaching  from  the  feed  hole  to  the  grate. 

Just  before  feeding  the  surface  of  the  oven  would  be  a  bright 
red  all  over,  which  would  gradually  cool  down  to  a  very  dull  red 
in  that  part  of  the  oven  .nearest  the  feed  hole  last  fed.  The 
weight  of  the  charge  of  wet  tan  fed  in  was  nearly  300  pounds. 
The  combustion  seemed  to  take  place  entirely  on  the  surface 
and  to  reduce  the  volume  of  the  cone  by  equal  decrements  of 
volume  from  all  parts  of  the  surface,  to  a  very  obtuse  cone  about 
60  inches  in  diameter  and  24  inches  high.  During  the  process 
of  combustion  the  oven  would  grow  steadily  hotter  to  the  end, 
and  would  be,  when  fed  again,  a  bright  red  heat,  probably 
about  1,800°. 

Silver  exposed  in  the  combustion  chamber  was  readily  melted 
at  all  times,  sometimes,  however,  a  little  sooner  than  at  others. 
The  shortest  time  was  about  30  seconds  and  the  longest  about  3 
minutes  required  to  melt  a  silver  "  dime."  A  piece  of  silver, 
however,  hung  on  a  chain  and  suspended  in  the  furnace  bypass- 
ing the  ends  of  the  chain  through  the  two  feed  holes,  the  posi- 
tion of  the  coin  being  about  midway  between  the  feed  holes  and 
between  the  grate  bars  and  the  crown  of  the  oven,  thus  being 
exposed  to  the  direct  action  of  the  flame  in  the  furnace  and  of 
the  radiant  heat  from  the  tan,  was  not  melted,  although  exposed 
during  the  whole  experiment.  This  must,  I  think,  have  been 
because  at  that  point  the  products  of  combustion  of  the  tan 
from  one  cone  were  diluted  with  the  air  which  would  afterward 
be  partly  consumed  by  the  tan  of  the  other  cone  on  its  way  to 
the  chimney.  There  was  a  perceptible  variation  of  the  color  of 
the  brick  work  of  the  arch,  when  the  tan  in  both  cones  was  con- 
suming, from  a  bright  red  at  the  end  nearest  the  boilers  to  a  dull 
red  at  the  end  farthest  from  the  boilers.  I  think  a  coin  exposed 
in  the  oven  between  the  second  cone  and  the  combustion  cham- 
ber would  have  been  melted  as  easily  as  in  the  combustion 
chamber,  although  this  is  only  an  opinion.  The  fact  that  the 
temperature  was  higher  after  passing  the  second  cone  than 
before  shows  that  there  was  a  greater  excess  of  air  in  the  prod- 
ucts of  combustion  before  passing  the  second  cone  than  after- 
ward, and  suggests  the  idea  that  several  successive  cones  of  in- 
candescent bark  (which  would  be  the  result  of  four  or  more  feed 
holes,  as  in  the  Hoyt  furnace),  might  still  further  reduce  the 
excess  of  air,  and  therefore  increase  the  temperature  of  the  gas. 


The  time  during  which  distillation  only  is  taking  place,  that  is, 
before  the  surface  of  the  cone  becomes  red,  does  not  exceed  five 
minutes,  but  it  is  probable  that  the  tan  is  only  dried  and  coked 
to  a  small  depth  during  that  interval,  and  that  the  continued 
distillation  goes  on  from  the  outer  layers  of  the  cone  from  the 
commencement  until  near  the  end.  On  raking  away  the  outer 
surface  of  the  tan  during  the  early  part  of  the  process,  the  fresh, 
green  undried  tan  will  be  found  underneath. 

All  brick  and  ironwork  around  passages  for  products  of  com- 
bustion from  oven  through  combustion  chamber  were  nearly  air- 
tight. Only  an  insensible  quantity  of  air  can  have  leaked  into 
the  flues  and  mingled  with  the  gas,  en  route,  until  the  back  con- 
nection is  reached.  This  was  of  sheet  iron  and  may  have  leaked 
considerable  air,  and  also  the  front  connection  may  have  leaked 
some  air. 

The  gases  on  reaching  the  back  connection  had  sufficient  tem- 
perature to  heat  a  small  spot  on  the  cast  iron  doors  to  a  dull  red 
heat  in  the  dark. 

The  amount  of  air  found  per  pound  of  dry  tan  in  the  products 
of  combustion  was  (by  means  of  the  velocity  of  smoke  in  the 
chimney)  10J  pounds.  The  relative  amounts  of  carbonic  acid 
and  free  oxygen  in  the  products  of  combustion  by  volume,  in  per 
cent,  of  the  dry  gas  : 

Carbonic  acid 11.1 

Free  oxygen 10.6 

The  heat  developed  was  (see  table),  (13-100  being  allowed  for 
radiation  per  pound  of  dry  tan),  7%  pounds  of  water  requiring 
6  pounds  of  air.  If  the  air  in  excess  is  10.6-11.1  of  the  car- 
bonic acid,  the  air  supplied  per  pound  of  dry  tan  would  be 
21.7-^-11.1X6=11.7,  or  nearly  a  coincidence. 

If  this  air  had  all  passed  through  the  combustion  chamber, 
the  temperature  could  only  have  been  (calculated  from  the) 

Elevation  of  temperature  of  10%  pounds  of  air,  1  pouid  of  fuel  and  1.22  pounds  of 
steam,  the  air  and  fuel  being  supplied  at  70  degrees  and  the  steam  at  212 
degrees  by  the  available  heat  in  the  pound  of  dry  tan  being  7%— 1.44=6.06. .  .1,800° 

Elevation  of  the  products  of  combustion  being  10%  pounds  air,  1  pound  fuel 
and  1.22  pounds  steam  from  the  temperature  of  the  chimney  510  degrees 
by  the  addition  of  the  heat  abstracted  by  the  steam  and  radiation  being 
4.43-f-.13=4.56 1,810° 

The  temperature  of  the  furnace  being  sufficient  to  melt  silver 
readily  (2,000°),  would  seem  to  show  that  an  amount  of  air 
equivalent  to  10  per  cent,  of  the  products  of  combustion,  or  1  4-10 
pounds  of  air,  had  leaked  in,  leaving  the  pounds  of  air  per  pound 
of  dry  tan  which  passed  through  the  furnace  9  1-10,  or  nearly 


the  same  in  proportion  to  the  heat  developed  as  was  found  at 
Wilcox,  or  1^  times  that  actually  necessary  for  perfect  combus- 
tion. It  must  be  acknowledged  that  this  furnace  was  injured  by 
10  per  cent,  of  cold  air  leaking  into  the  flues  between  the  com- 
bustion chamber  and  the  chimney. 

Notwithstanding  this  excess  of  air  there  is  an  amount  of  heat 
equivalent  to  1  1-10  pounds  of  steam  which  was  not  developed 
by  combustion,  being  about  12  per  cent,  of  the  heat  in  the  tan 
or  25  per  cent,  of  the  heat  realized  on  the  steam  in  the  boilers. 

The  cause  of  the  incomplete  combustion  was  probably  partly 
due  to  the  small  supply  of  air,  for  it  has  been  found  that  in  order 
to  burn  all  the  combustible  gas  coming  from  bituminous  coal  in 
an  ordinary  furnace,  the  products  of  combustion  must  be  diluted 
with  40  per  cent,  of  their  volume  of  air.  In  the  case  of  the  wet 
tan  at  Weed's  furnace  the  products  of  combustion  of  the  tan  in 
air  were  already  diluted  with  40  per  cent,  of  their  volume  of 
steam,  and  therefore  in  order  that  the  proportion  of  consumed 
gas  and  the  nitrogen  and  water  diluting  it  should  be  the  same  as 
in  the  case  of  bituminous  coal,  the  supply  of  air  must  be  1|  that 
actually  necessary  for  combustion. 

There  is  a  way  in  which  the  performance  of  the  Thompson 
furnace  is  sometimes  injured,  and  in  which  many  of  the  earlier 
Thompson  ovens  that  did  not  succeed  were  probably  injured, 
that  is,  by  a  too  great  contraction  of  the  flue  leading  from  the 
oven  to  the  combustion  chamber.  The  effect  is  the  same  as  on 
the  Crockett  furnace  at  Great  Bend.  The  effect  of  the  contrac- 
tion at  Binghamton  will  be  considered  further  on. 

These  outlets  were  arranged  as  shown  in  the  plans  and  had  an 
area  of  3  6-10  square  feet  for  each  pair  of  ovens,  being  1-23  the 
grate  surface.  The  cross  section  of  the  tubes  in  one  boiler  was 

2  8-10  square  feet.     The  temperature  of  the  gas  on  leaving  the 
furnace  was  nearly  2,000°,  and  at  the  entrance  to  the  tubes 
1,000°.     The  volumes  of  gas  were  then  in  the  ratio  of  5  to  3, 
and  the  area  of  the  passages  in  the  ratio  of  4  to  3,  indicating 
that  the  passage  from  the  furnace  to  the  combustion  chamber 
might  have  been  enlarged  at  least  1-4  with  benefit  to  the  boiler 
without  reference  to  the  combustion. 

THOMPSON  FURNACE  AT  BBACKNEYVILLE. 

This  furnace  was  similar  to  the  one  at  Binghamton  except  that 
there  were  two  flue  boilers,  each  3  feet  9  in  diameter  and  20  feet 
long,  with  two  flues  in  each  boiler  12  inches  in  diameter.  Only 

3  of  the  4  ovens  were  in  use,  the  fourth  being  bricked  off  by  a 


29 

'<#> 

t 

brick  wall  in  the  opening  into  the  combustion  chamber.  I  had 
no  means  of  knowing  how  nearly  air-tight  this  wall  was. 

The  average  rate  of  combustion  was  73-100  pounds  of  dry  tan 
per  square  foot  per  hour,  but  as  in  one  boiler  it  was  97-100  and 
in  the  other  49-100,  the  average  does  not  measure  the  relative 
economy. 

Silver  could  be  melted  in  the  combustion  chamber  (the  one 
connected  to  the  pair  of  ovens)  but  could  not  be  introduced  into 
the  oven. 

The  performance  of  this  furnace  was  in  every  respect  similar 
to  the  one  at  Binghamton,  except  that  as  the  rate  of  combustion 
was  only  one-half  as  much  per  square  foot  of  grate  the  ovens 
were  only  fed  half  as  often.  There  was  no  system  of  alternate 
feeding,  and  no  changing  of  the  ash  pit  doors. 

The  furnace  was  not  in  as  good  repair  as  at  Binghamton. 

The  pounds  of  air  per  pound  of  dry  tan  were  found  to  be  18, 
by  the  velocity  of  the  smoke  in  the  chimney,  and  by  the  analysis, 
of  gas  as  before,  17  9-10  pounds. 

Assuming  the  18  pounds  of  air  as  nearest  correct  we  find  for 
the  temperature  of  the  furnace,  computed  as  before  : 

From  thermal  equivalent  of  tan 1 ,320° 

From  temperature  of  chimney  and  steam 1,350° 

1,3352 

From  which  may  be  computed  the  proportion  the  air  found  in 
the  chimney  bears  to  the  air  passing  through  the  furnace,  in  order 
that  the  combustion  chamber  may  have  a  temperature  of  1,800°, 
and  the  weight  of  air  that  passed  through  furnace  : 

Pounds  of  air  per  pound  dry  tan 12 

Ratio  of  air  necessary  to  air  supplied 100  :175 

The  weight  of  air  leaking  into  the  flues  between  the  oven  and 
the  chimney  was  6  pounds  per  pound  dry  tan. 

HOYT  FURNACE  AT  WILCOX. 

This  furnace  consists  of  two  pairs  of  ovens,  each  pair  of  ovens 
being  connected  with  3  horizontal  flue  boilers.  Each  oven,  with 
its  boilers,  is  entirely  independent  of  the  other,  each  being  fur- 
nished with  a  separate  feed  pipe,  steam  pipe,  water  tank,  safety 
valve  and  injector.  The  only  things  in  common  between  the  two 
ovens  are  the  fire-room  and  the  chimney. 

The  chimney  is  of  brick,  107  feet  high  above  the  grate. 

The  ovens  are  each  6  feet  wide  and  16  feet  long. 

The  grates  are  of  iron,  the  width  of  the  bar  being  7-16  inches 
and  of  the  space  7-32  inches. 


The  ash  pits  are  the  entire  width  of  the  grate  and  entirely 
open  in  front,  no  doors  being  provided. 

The  distance  from  the  under  side  of  the  grate  bars  to  the 
bottom  of  the  ash  pit  is  4  feet  9  inches.  This  great  height  allows 
a  double  current  of  air  to  form  in  the  ash  pit,  the  cold  one  enter- 
ing at  the  front  near  the  bottom,  passing  toward  the  back  end, 
becoming  gradually  warmed  by  the  radiant  heat  from  the  grate, 
rising  and  returning  close  under  the  grate,  part  entering  through 
the  grate  to  the  ovan,  and  the  balance  finally  passing  out  of  the 
ash  pit  at  the  front  at  a  temperature  of  300°.  Under  these  cir- 
cumstances the  temperature  of  the  ash  pit  is  about  200°. 

If  the  furnace  is  so  far  closed  as  to  prevent  the  return  current 
of  air,  that  is,  if  the  opening  is  reduced  from  24  square  feet  to 
7j  of  1  square  foot,  the  temperature  of  the  ash  pit  rises  to  about 
that  of  the  Crockett  furnace,  500°. 

When  the  front  is  open  there  is  a  small  loss,  due  to  heating 
the  air  which  returns  to  about  300°. 

There  is  no  contraction  of  the  flue  from  the  oven  to  the  space 
under  the  boilers,  the  opening  being  the  full  width  of  the  oven. 

There  are  four  feed  holes,  each  one  foot  in  diameter,  in  each 
oven.  The  tan  is  fed  in  through  these  holes  as  it  burns  down, 
and  the  holes  sealed  by  wet  tan  kept  all  over  the  floor  about  two 
feet  deep. 

The  bark  is  brought  about  250  feet  by  a  conveyor  from  the 
leaches,  and  may  be  delivered  at  any  point  on  the  floor  by  open- 
ing a  suitable  shoot. 

This  furnace  was  the  most  complete  in  all  its  appurtenances, 
being  of  originally  the  best  design  and  in  the  best  condition  of 
any  experimented  upon.  The  boilers  were  new  and  tight,  the 
brick  work  sound;  and  all  parts  of  the  boiler  and  smoke  connec- 
tion protected  from  loss  of  heat  by  radiation.  The  chimney  was 
of  brick. 

There  were  dampers  in  the  flues  leading  from  the  boilers  to 
the  chimney.  The  cross- section  of  these  flues  was  4  square  feet 
each.  In  the  case  where  the  most  tan  was  burned  the  damper 
was  kept  wide  open,  and  in  the  case  where  the  least  was  burned 
it  was  kept  at  an  angle  of  45°  in  the  pipe,  the  effect  being  to 
reduce  the  area  to  about  2  square  feet. 

The  pounds  of  dry  tan  burned  per  hour  were  respectively  1,000 
and  750,  or  a  proportion  of  6-10  and  4-10  square  inches  to  one 
pound  of  dry  tan  per  hour.  This  opening  was  not  the  con- 


31 


trolling  section  in  the  first  case,  although  it  was  in  the  second.* 

The  performance  of  the  furnace  during  the  first  experiment'does 
not  correspond  with  the  maximum,  which  might  be  25  per  cent, 
more,  or  1,250  pounds  of  dry  tan  per  hour,  or  J  of  a  cord.  The 
draught  was  checked  in  this  experiment  by  a  thick  bed  of  ashes 
which  had  been  accumulating  on  the  grate  without  being  raked 
out  for  10  days.  During  this  time  the  ashes  had  accumulated  8 
inches  to  12  inches  deep.  The  other  furnace  had  not  been  raked 
out  for  4  days. 

No  ashes  or  embers  fell  through  the  grate  at  any  time.  The 
ash  pits  were  raked  out  in  expectation  that  some  would  collect, 
but  were  found  perfectly  clean  at  the  end  of  the  experiment.  It 
is  customary  to  rake  out  the  furnace  through  the  8  doors  provided 
every  fortnight.  If  it  were  required  to  drive  the  furnace  to  its 
utmost  it  would  be  necessary  to  rake  them  out  every  week  at 
least. 

The  action,  manner  of  feeding,  and  appearance  of  the  Hoyt 
furnace  in  both  experiments  is  very  similar  to  the  Thompson 
furnace  already  described,  except  that  the  temperature  of  the 
oven  was  more  nearly  uniform,  and  there  never  was  any  smoke 
forced  back  into  the  fire  room  through  the  feed  holes. 

The  fires  weie  watched  through  the  small  registers  provided 
in  each  furnace  door,  and  were  filled  up  when  burned  down. 
They  were  generally  allowed  to  burn  down  lower,  i.  e.,  further 
from  the  crown  of  the  furnace  than  at  Binghamton  or  Brackney- 
ville,  the  greater  height  of  the  furnace,  6  feet  in  place  of  4£  feet, 
allowing  this. 

In  this  connection  it  must  be  remembered  that  while  the  rate 
of  combustion  per  square  foot  of  grate  surface  was  at  Weed's 
the  same  as  at  Wilcox  (2),  and  therefore  the  rate  of  com- 
bustion per  square  foot  of  superficial  area  of  the  cones  of  tan 
the  same,  the  actual  weight  of  tan  in  the  furnace  undergoing  the 
processes  of  drying  and  coking  was  nearly  2J  times  as  much  at 
Wilcox  as  at  Weed's,  and  therefore  the  performance  of  the  fur- 
naces, so  far  as  all  phenomena  regarding  the  intermitted  action 
of  the  drying  and  coking  are  concerned,  are  not  comparative. 

There  was  no  smoke  coming  from  the  chimney  at  any  time 
during  the  experiments. 


*The  openings  of  6-10  and  4-10  square  inches  for  one  pound  of  dry  tan  burned  per 
hour  are  equivalent  to  8-10  and  6-10  square  inches,  with  a  chimney  80  feet  hia:h,  and 
having  a  temperature  of  600  degrees  inside  and  60  degrees  outside,  as  in  the  case  of 
Wells'. 


A  silver  coin  exposed  in  the  back  end  of  the  oven  melted 
nearly  as  soon  as  at  Weed's,  in  about  60  seconds. 

Much  of  the  air  for  combustion  came  through  the  registers  in 
the  furnace  doors,  for  although  these  registers,  except  for  a  few 
seconds  when  looking  at  the  fire,  were  kept  shut,  they  were  only 
iron  casting,  and  must  have  leaked  considerably  through  the 
badly  fitting  joints.  I  do  not  consider  that  the  air  leaking  in 
here  did  any  harm,  but  acted  as  efficiently  as  if  it  had  come 
through  the  grate. 

When  these  registers  were  opened  to  examine  the  fire,  the 
surface  of  the  heaps  of  tan  appeared  to  be  covered  with  about 
equal  portions  of  black  and  red  cinders,  and  would  begin  to 
scintillate  and  grow  rapidly  red  when  the  air  from  the  register 
touched  it,  showing  that  at  that  part  of  the  furnace  at  least,  the 
oxygen  in  the  air  surrounding  the  heaps  of  tan  was  reduced 
below  the  point  of  dilution  necessary  to  insure  a  rapid  com- 
bustion. 

A  considerable  amount  of  heat  was  lost  by  radiation  from  the 
oven  doors.  There  were  8  of  these  doors  to  each  furnace,  and 
they  all  became  a  dull  red  in  the  dark  over  about  1  square  foot 
of  their  surface,  the  atmosphere  outside  being  30°. 

The  labor  of  firing  at  this  furnace  was  very  small,  owing  to 
the  convenient  arrangement  for  delivering  the  tan  on  the  fire 
room  floor.  One  man  fired  usually  both  furnaces  and  tended  to 
the  water  during  the  day,  thus  handling  usually  10  cords,  or 
40,000  pounds,  of  wet  tan  in  12  hours. 

If  the  temperature  of  these  ovens  as  actually  measured  be 
compared  with  the  calculated  temperature  by  the  two  methods 
as  before,  taking  the  air  at  10  pounds  per  pound  of  dry  tan,  we 
have  the  following  : 

Wilcox  (1)  Wilcox  (2) 
Temperature  of  oven  computed  from  the  known  weight  of  air  and 

the  thermal  equivalent  of  the  tan 2,060°  2,060° 

Temperature  of  oven  computed  from  the  Leat  given  up  by  products 

of  combustion  to  steam  and  adding  temperature  of  chimney. . .  .2,050°  2,080Q 


2,055°  2,070° 

Average 2,060° 

This  temperature  is  a  little  in  excess  of  that  estimated  from  the 
melting  point  of  silver,  showing  that  no  air  can  have  leaked  into 
the  flues  between  the  oven  and  the  chimney. 

The  air  for  combustion  was  then  10  pounds  per  pound  of  dry 
tan,  being  1  40-100,  that  actually  necessary  for  combustion,  or  40 
per  cent,  of  "  air  in  excess,"  being  less  than  at  any  other  place 


33 


where  the  combustion  was  perfect.  I  think  this  may  be  due  to 
the  long  oven  and  4  cones  of  tan,  by  means  of  which  the  air  in 
the  furnace  is  intermingled,  and  each  particle  brought  in  contact 
with  surface  of  tan. 

LEACHED  BARK. 

Wood  (and  inferentially  bark)  is  said  by  M.  Violet  to  consist  of 
a  fibrous  substance  called  "cellulose,"  which  is  insoluble  in 
water,  surrounded  by  a  material  which  is  richer  in  carbon  and 
hydrogen.  This  encrusting  material  consists  mainly  of  sugar, 
starch,  gum,  resin,  glucose  and  tannin.  All  of  these,  except  the 
resin,  are  soluble  in  hot  or  cold  water,  and  are  probably  wholly  or 
partially  extracted  in  the  process  of  leaching. 

They  are  all  compounds  of  hydrogen,  oxygen  and  carbon,  but 
being  rich  in  oxygen  will  develop  by  combustion  but  a  small 
amount  of  heat.  On  the  other  hand,  the  resin,  which  is  per- 
fectly insoluble  in  water,  and  must  remain  entire  in  the  bark 
after  the  most  thorough  leaching,  contains  no  oxygen,  and  has  a 
thermal  equivalent  of  nearly  22  pounds  of  water  evaporated  from 
212°,  or  about  three  times  as  much  as  the  soluble  constituents. 

It  would  appear  then  that  the  thermal  equivalent  of  leached 
bark  must  be  more  than  of  green  or  unleached  bark. 

The  average  thermal  equivalent  of  the  soluble  constituents  of 
the  bark  is  6J  pounds  of  water  evaporated  from  212°,  and  of  the 
unleached  bark  (as  has  been  already  determined),  8J  pounds  of 
water  evaporated  from  212°. 

There  will  be  extracted  from  a  cord  of  unleached  bark  in  the 
process  of  leaching,  if  thoroughly  done,  600  pounds  of  soluble 
matter,  and  the  remainder  will  weigh  1,400  pounds  when  dried 
at  110°  C. 

If  the  thermal  equivalent  of  a  pound  of  the  bark  as  leached  at 
the  tanneries  in  the  different  experiments,  be  calculated  on  the 
basis  that  the  original  equivalent  was  8J  pounds,  and  that  a  cord 
of  leached  bark  has  lost  the  balance  of  its  actual  weight,  and 
2,000  pounds  of  soluble  material  having  an  equivalent  of  6£ 
pounds,  we  shall  find  for  the  thermal  equivalent  of  each  bark  in 
pounds  of  water  evaporated  from  212°  by  one  pound  of  bark  dried 
at  110°  C. : 

Stevens' 8.9  Wells'  (2j 9.0 

Wells' (1) 9.0  Wilcox  (1)  and  (2) 9.0 

Brackneyville 8.9  Wells'  (3) 8.9 

Weed 8.6  Wells'  (4) 8.9 

This  would  be  the  weight  of  water  evaporated  or  the  weight  of 
steam  formed  in  the  boiler  by  the  combustion  of  one  pound  of  ta> 


34 


if  the  combustion  in  the  oven  were  perfect,  and  if  the  boiler  sur- 
face were  sufficiently  extended  to  reduce  the  products  of  combus- 
tion to  the  same  temperature  as  the  outside  air,  or  about  60°. 

It  will  be  seen  that  only  about  one-half  of  this  amount  was 
evaporated  in  any  case,  and  generally  less  than  one-half. 

There  are  four  principal  reasons  for  this  discrepancy  : 

1.  Water  in  the  bark. 

2.  Imperfect  combustion. 

3.  Radiation. 

4.  Heat  carried  away  in  the  chimney  gas. 

The  first  of  these  is  entirely  independent  of  the  oven  or  boilers, 
and  if  the  proportion  of  water  to  bark  were  the  same,  might  be 
neglected  in  every  case  without  affecting  the  comparison.  Unfor- 
tunately the  proportion  of  water  varies  in  every  case.  The  water 
put  into  the  oven  with  the  bark  has  to  be  evaporated,  and  absorbs 
the  same  amount  of  heat  in  being  evaporated  as  though  it  were 
put  into  the  boiler.  ^ 

It  also  lowers  the  temperature  of  the  oven,  thus  injuring  the 
effect  of  the  heating  surface. 

It  also  dilutes  the  air  entering  the  furnace,  so  that  probably  the 
wetter  bark  will  require  a  larger  excess  of  air  for  equally  perfect 
combustion. 

The  heat  in  a  pound  of  dry  bark  that  is  available,  then,  is  the 
total  heat  given  above  reduced  by  the  heat  necessary  to  evaporate 
the  water  in  the  bark,  and  to  superheat  it  to  the  temperature  of 
the  chimney  (see  table)  and  will  be  : 

Stevens' 6.9       Wilcox  (1) 6.8 

Weils'(l) 6.9       Wilcox  (2) 6.9 

Brackneyville 7.0       Wells' (3) : 6.9 

Weed 7.0       Wells' (4) 6.9 

Wells' (2) 7.0 

This  is  the  weight  of  water  that  might  be  evaporated  from  the 
boiler  by  each  pound  of  dry  tan.* 

INCOMPLETE   COMBUSTION. 

Generally  in  all  cases  a  portion  of  the  heat,  about  5  per  cent., 
is  lost  by  incomplete  combustion.  No  analysis  of  the  chimney 
gas  has  been  made  in  these  experiments  that  will  show  how  per- 
fect the  combustion  was.  It  can  only  be  inferred  from  the 
amount  of  heat  accounted  for  in  all  other  ways,  probably  being 

*The  injurious  effect  of  a  small  proportion  of  water  in  fuel  is  much  less  than  is  gen- 
erally supposed.  A  mixture  of  100  parts,  containing  13  parts  of  wood  and  87  parts  of 
water,  will  develop  sufficient  sensible  heat  to  raise  the  products  of  combustion  to  the 
temperature  necessary  for  ignition,  about  500  degrees.  The  same  is  true  of  a  mixture 
containing  7  per  cent,  of  charcoal  and  93  per  cent,  of  water. 


at  least  2J  per  cent,  in  the  best  case  (Hoyt's  furnace  at  Wilcox), 
and  much  more  in  the  worst. 

KADIATION. 

This  loss  depends  upon  the  form,  arrangement  and  dimensions 
of  the  furnace  and  boiler,  the  absolute  amount  being  in  general 
proportioned  to  the  surface  of  brick  or  stone  work  exposed.  All 
the  furnaces  must  have  suffered  considerably  from  radiation,  but  if 
we  neglect  the  heat  radiated  by  the  brick  work  over  the  oven, 
which  is  utilised  in  partly  drying  and  heating  the  tan  in  all  fur- 
naces fed  from  the  top,  all  the  furnaces  were  injured  probably 
nearly  alike,  Wells'  2,  3  and  4  being  injured  most  by  radiation  from 
brick  work,  and  Weed  most  from  radiation  from  sheet  iron  work 
in  back  connection,  and  Wilcox  by  radiation  from  furnace  doors.* 

CHIMNEY  GAS. 

The  heat  carried  away  in  the  chimney  gas  amounts  to  30  per 
cent,  in  Wells'  (1)  and  15  per  cent  in  Weed's. 
It  depends  upon  two  items,  viz. : 

1.  The  excess  of  temperature  of  the  chimney  gas  over  the  out- 
side air. 

2.  The  weight  of  the  gas  in  comparison  with  the  weight  of  the 
fuel. 

The  nearer  the  temperature  of  the  gas  is  to  the  temperature  of 
the  atmosphere,  the  less  heat  will  be  carried  off  in  the  gas.  It  is 
the  duty  of  the  boilers  to  reduce  the  gas  to  the  temperature  of  the 
chimney  from  the  temperature  of  the  furnace.  If  the  chimnies  have 
the  same  temperature  the  boilers  may  be  considered  equally  efficient, 
whatever  may  be  the  extent  or  arrangement  of  their  surface,  provided 
no  heat  is  lost  by  radiation,  and  no  cold  air  leaks  into  the  flues, 
from  the  outside. 

All  the  boilers  tested  were  injured  by  a  certain  amount  of  air 
which  leaked  into  the  flues  from  the  outside,  generally  through  the 
fissures  in  the  brick  work  or  through  the  joints  in  the  sheet  iron 
work.  Probably  Stevens'  and  Wells'  suffered  most  from  this 
cause.  At  these  furnaces  the  stone  and  brick  work  was  old  and 
full  of  fissures.  During  the  many  years  they  had  been  in  use  the 
alternate  contraction  and  expansion  of  the  walls  had  forced  out 
the  mortar  from  the  joints.  During  some  stages  in  the  combus- 
tion smoke  issued  from  these  fissures,  showing  that  there  were  open- 

*The  surfaces  exposed  for  radiation  were  (iron  work)  : 

Wet  d,  surface  bark  connection ....  50  square  feet    gas  inside ....  1,000U    outside  . 
Wilcox,  surface  furnace  doors 50  square  feet    gas  inside ....  2,000°    outside ....  30 


36 


ings  through  the  wall,  and  that  the  air  must  flow  in  when  the 
pressures  were  reversed. 

Brackneyville  was  nearly  tight  in  the  brick  work,  as  were  Weed 
and  Wilcox,  but  all  these  were  injured  by  air  leaking  in  through 
the  sheet  iron  work  around  the  back  connection. 

I  have  no  means  of  estimating  the  amount  of  air  leaking  in 
through  the  flues,  but  should  consider  that  it  may  have  been  in- 
sensibly small  at  Wilcox. 

In  addition  to  the  air  leaking  into  the  flues  some  air  leaked  into 
the  chimney  between  the  boiler  and  the  thermometer.  This  air 
had  no  effect  on  the  economy  of  the  boiler,  but  only  reduced  the 
temperature  of  the  chimney  and  injured  the  draught.  The  tem- 
perature of  the  chimney,  as  measured  by  the  thermometer,  cannot 
be  taken  as  a  measure  of  the  efficiency  of  the  boiler  surface.  In 
Wells'  and  Stevens'  in  particular  there  were  large  cracks  around 
the  junction  of  the  smoke  stack  with  the  boiler. 

The  leakage  of  air  into  the  chimney  had  no  effect  upon  the 
amount  of  heat  carried  away  by  the  chimney  gas,  the  temperature 
being  lowered  as  fast  as  the  weight  was  increased. 

WATER  ENTRAINED  WITH  STEAM. 

The  measurements  taken  to  determine  the  water  hi  the  steam 
are  given  in  the  appendix.  The  results  are  as  follows : 

Per  cen^.  of  water  in  steam.    Pounds  per  hour. 

Wells'  fl) 1-*  33 

Rrackneyville 7.9  95 

Weed 3.4  188 

Wells' (2).. 3.5  55 

Wilcox,  superheated ." 24° 

The  close  approximation  of  the  absolute  amount  of  water  car- 
ried from  the  boiler  in  the  two  experiments  at  Wells'  suggests  the 
idea  that  this  water  was  due  to  some  condensation  of  the  steam 
after  it  had  left  the  water  in  the  boiler  as  dry  steam. 

There  was  considerable  surface  exposed  to  the  cold  air  in  every 
case,  being  generally  the  surface  of  the  steam  drums  and  pipes, 
and  in  some  cases  the  tops  and  ends  of  the  boilers. 

The  amount  of  surface  in  each  case  can  be  approximately  com- 
puted from  the  plans  accompanying  this  report,  and  was  as 
follows : 

Wells' '•  40  square  feet 

Brackneyville 130  square  feet 

Weed's 250  square  feet 

Wilcox  (to  atmosphere  at  70  degrees) 60  square  feet 

Wilcox  (to  gas  in  furnace  at  2,000 degrees) 50  square  feet 


3T 


And  therefore  the  pounds  of  water  entrained  with  the  steam  for 
each  square  foot  of  surface  exposed  per  hour  :  , 

Wells'   (2) 1.325 

Wells'  (1) 0.825 

Brackneyville « 0.731 

Weed's 0.752 

A  perfectly  clean  steam  pipe  filled  with  steam  at  60  pounds 
pressure,  and  exposed  to  the  still  air  at  80°  temperature  will  con- 
dense steam  at  the  rate  of  three-fourths  of  a  pound  per  square 
foot  per  hour. 

The  close  agreement  of  the  weight  of  water  entrained  with  the 
steam,  and  the  weight  of  water  that  must  have  been  condensed  by 
the  cold  air  on  the  outside  of  the  pipe,  leaves  no  escape  from  the 
conclusion  that  the  water  in  the  steam  ivas  entirely  due  to  condensa- 
tion in  every  case. 

As  far  as  the  ill  effect  of  a  certain  proportion  of  water  on  the 
steam  when  used  in  an  engine  for  heating  liquor  or  other  pur- 
poses is  concerned,  it  can  make  no  difference  whether  the  water 
has  been  condensed  from  the  steam  or  whether  it  is  carried  from 
the  boiler  as  ivater,  without  ever  having  been  steam  at  all ;  but  as 
far  as  the  heat  abstracted  from  the  fuel  by  the  steam  is  concerned, 
it  does  make  a  very  important  difference,  the  heat  abstracted 
from  the  fuel  by  the  steam  being  the  same  whether  any  of  it  or  all 
of  it  is  afterward  condensed,  reaching  the  engine  as  all  steam, 
partly  steam  and  partly  water,  or  all  water. 

The  heat  abstracted  from  the  fuel  in  the  last  case  being  that 
required  to  evaporate  all  the  feed  water  pumped  in. 

It  is  therefore  necessary  in  such  experiments  to  pay  particular 
attention  to  the  amount  of  surface  exposed  to  the  cold  air. 

TEMPERATURE  OF  CHIMNEY. 

The  temperature  of  the  chimney  as  shown. by  thermometer  and 
the  temperature  of  the  atmosphere,  the  difference  being  one  ele- 
ment of  the  portion  of  heat  lost,  were  : 


Temperature  of  chimney  gaF....  700°    5&)0    580°    510°    420°    700°    580°    490°    480° 
Temperature  of  atmosphere 50°      70°      50°      65°      50°      70°      70°      30°      80° 

Difference 650°    510°    530°    445°    370°    630°    510°    460°    450° 

PRIMING. 

The  priming  was  therefore  nothing  in  all  of  the  boilers  experi- 
mented on.     This  agrees  with  all  reliable  experiments  I  have  ever 


3s 


seen,  the  water  primed  as  shown  by  the  experiment  being  less  than 
the  instrument  could  be  relied  upon  to  detect.  The  weight  of 
water  pumped  in  is  therefore  a  measure  of  the  steam  formed. 

ABSOLUTE   EFFICIENCY. 

The  absolute  efficiency  of  all  the  furnaces,  as  indicated  by  the 
experiment,  being  the  heat  utilized  in  the  steam  compared  with 
the  available  heat  in  the  tan,  or  the  proportion  that  the  steam 
actually  evaporated  bears  to  the  steam  which  might  be  evapo- 
rated by  the  same  tan  in  a  perfect  furnace  and  boiler,  no  allow- 
ance being  made  for  imperfect  combustion,  insufficient  heating 
surface  or  radiation,  are  as  follows  : 


Stevens' 33.6 

Wells'  (1) 44.5 

Brack  neyville 57.1 

Weed 64.7 

Wells'  (2) 45.8 


Wilcox   (1) 68.9 

Wilcox   (2) 75.7 

Wells'  (3) 61.1 

Wells'  (4) 57.3 


The  only  furnaces  that  are  fairly  comparable  are  those  at  the 
same  rate  of  combustion  per  square  foot  of  boiler  surface.  The 
rates  of  combustion — that  is,  the  pounds  of  dry  tan  burned  per 
square  foot  per  hour,  were  : 

Stevens' 1.61        Wilcox  (1) 1.05 

Wells'  (1) 0.98        Wilcox  (2) 0.79 

Brackueyville 0.73        Wells'  (3) 0.63 

Weed 0.67        Wells'  (4) 0.63 

Wells'  (2) 0.64 

Of  these  experiments  Wells'  (1)  and  Wilcox  (1)  are  at  nearly  the 
same  rate ;  also  Brackneyville  and  Wilcox  (2) ;  also  Weed  and 
Wells'  (3) ;  Wells'  (2)  and  (4)  and  Stevens'  being  out  as  experi- 
ments made  under  exceptional  conditions. 

Comparing  the  experiments  together,  then,  that  have  the  same 
rate  of  combustion,  there  results  : 

Hoyt.  Crockett. 

Pounds  dry  tan  bnrned  per  square  foot  of  heating  sur- 
face per  hour 1.05  0.98 

Absolute  efficiency 0.689  0.445 

Eelative  efficiency 100.  64. 

For  the  next  lowest  rate  of  combustion  : 

Hoyt.  Thompson. 
Pounds  of  dry  tan  burned  per  square  foot  of  heating 

surface  per  hour 0.79  0.73 

Absolute  efficiency 0.757  0.571 

Belative  efficiency 100.  76. 

For  the  lowest  rate  of  combustion  : 

Thompson.  Crocket*. 
Pounds  dry  tan  burned  per  square  foot  of  heating  surface 

per  hour     0.67  0.63 

Absolute  efficiency 0.647  0.611 

Belative  efficiency 106.  100. 


39 

8J5J— 

If 

Although  the  experiments  at  Brackneyville  and  Wells'  (1)  can- 
not be  compared  directly  together,  they  are  both  compared  with 
the  same  furnace  at  different  rates  of  combustion,  and  the  result- 
ing ratios  may  be  compared  (that  is,  76  and  64),  the  final  ratio 
being  100  and  118.  The  final  ratios  then  are  (each  furnace  being 
at  the  same  rate  of  combustion)  : 

Hoyt 122 

Thompson Ill 

Crockett 100 

These  are  the  actual  experimental  comparative  efficiencies  of 
two  Thompson,  two  Hoyt  and  two  Crockett  furnaces,  furnace  being 
taken  in  the  actual  condition  found. 

The  question  now  arises,  "  How  much  of  this  difference  is  due 
to  the  principle  of  construction  and  how  much  to  the  superiorities 
or  defects  of  each  particular  furnace." 

The  answer  to  this  question  may  be  very  accurately  inferred 
from  the  figures  already  given  in  the  report. 

The  main  causes  of  difference  are  : 

1.  Incomplete  combustion. 

2.  Dilution  of  air  either  passing  through  fire  or  leaking  into 
flues. 

INCOMPLETE   COMBUSTION. 

The  table  at  the  end  shows  the  total  heat  accounted  for  in 
the  six  cases  where  the  air  passing  up  the  chimney  was  measured, 
as  follows : 

Wells  (1).  Brack.  Weed.  Wcox  (1).  Wi!cox(2).  Wells  (3). 

Steam 3.03  4.01  4.53  4.61              5.30  4.17 

Water  in  bark 2.28  1.91  1.61  2.19              2.09  2.07 

Gas 2.94  2.40  1.33  1.73              1.40  1.96 

Water  of  combustion 0.45  0.45  0.50  0.45              0.45  0.45 

Sum  of  above  four  quantities..  .8.70         8.77         7.97  8.98  9.24  8.65 

Calculated  thermal   equivalent 
of  bark 9.00         8.90         8.60  9.00  9.00  8.90 

Difference    being   heat    unac- 
counted for  from  all  causes.  .0.30      —0.13      —063  +0.02  +0.24  —0.25 

It  appears  from  the  above  that  the  combustion  was  sensibly 
complete  in  all  except  Brackneyville  and  Weed  (the  discrepancies 
between  Wilcox  (1)  and  (2)  showing  the  limit  of  accuracy  of 
experiment). 

INCOMPLETE  COMBUSTION  CAUSED  BY  CONTRACTED  FLUE. 

There  is  a  way  in  which  the  contracted  opening  from  the  oven 
into  the  flue  may  act  injuriously  in  the  Thompson  furnace  if  car- 
ried to  excess,  and  is  positively  a  cause  for  the  failure  of  many 


of  the  earlier  Thompson  ovens,  and  for  the  incomplete  combus- 
tion of  the  Weed  furnace. 

If  the  opening  from  the  oven  into  the  combustion  chamber  is 
as  much  contracted  that  it  is  the  controlling  section,  that  is  to 
say,  if  it  is  so  small  that  the  principal  resistance  offered  to  the 
flow  of  the  gas  from  the  ash  pit  door  to  the  chimney  top  is  at 
this  point,  then  a  considerable  portion  of  the  combustible  gas 
will  escape  unburnedc 

The  cord  of  wet  tan  as  fed  into  the  furnace  contains  : 

Water 2,700  pounds. 

Gas 870  pounds. 

Fixed  carbon 600  pounds. 

Ashes 30  pounds. 

If  completely  burned  the  products  of  combustion  will  be  at 
the  temperature  of  the  furnace  (say  1,800°)  and  will  have  the  fol- 
lowing volume  : 

Steam .' 240,000  cubic  feet. 

Gas  and  steam  and  air 300,000  cubic  feet. 

Carbonic  acid  and  air 600.000  cubic  feet. 

1,140,000  cubic  feet. 

It  appears,  then,  that  there  must  pass  through  the  outlet  of  the 
furnace  1,140,000  cubic  feet  for  every  cord  of  tan  burned. 

At  the  Weed  furnace  there  was  burned  in  each  oven  one-eight 
of  a  cord  per  hour,  and  therefore  there  must  have  passed  through 
each  outlet  140,000  cubic  feet  per  hour. 

If  the  outlet  had  been  the  controlling  section,  it  would  have 
passed  this  volume,  or  2,300  feet  per  minute  and  no  more. 

The  ovens  were  fed  nearly  every  hour,  and  therefore  the  weight 
of  the  charge  must  have  been  ^(4,200)= 505  pounds,  containing 
a  volume  of  steam  and  gas  that  will  be  generated  soon  after  its 
entrance  into  the  furnace,  equal  to : 

Steam 30,000  cubic  feet. 

Combustible  gas 10,000  cubic  feet. 

40,000  cubic  feet. 

being  a  volume  sufficient  to  fill  all  outlet  from  the  furnace  and 
completely  arrest  the  inflow  of  air,  during  17  minutes,  if  the  gas 
and  steam  were  completely  driven  off  in  this  time. 

The  loss  in  this  case  would  be  the  heat  equivalent  to  all  the 
combustible  gas,  or  about  25  per  cent. 

The  process  of  completely  drying  and  coking  the  tan  lasts 
during  the  whole  time,  from  one  time  of  feeding  until  another, 
but  is  most  rapid  during  the  first  ten  minutes,  and  probably  nearly 
all  the  gas  generated  during  the  first  ten  minutes  in  the  Weed 


41 


furnace  was  lost.  The  actual  loss  of  heat  from  incomplete  com- 
bustion was  about  8  per  cent.,  indicating  that  one-third  of  the 
gas  passed  away  unconsumed  in  this  way. 

The  fact  that  there  was  a  pressure,  or  at  all  events  an  equili- 
brium of  the  gas  in  the  furnace  over  the  atmosphere,  just  after 
firing,  was  shown  by  the  fact  that  the  smoke  from  the  tan  in 
the  feed  holes  returned  into  the  fire  room  at  this  time,  and  kept 
it  so  full  of  smoke  as  to  be  almost  unendurable. 

This  was  not  so  at  Brackneyville  or  Wilcox. 

In  order  that  the  outlet  from  the  "Weed  oven  should  be  the 
controlling  section  it  must  have  an  area  of  less  than  3  square 
feet,  for  the  opening  into  the  ash  pit  that  only  passed  air  at  60° 
was  \  one  square  foot. 

The  actual  area  may  be  computed  from  Wells'  (4),  when  the 
outlet  was  reduced  until  it  was  the  controlling  section,  and  must, 
be,  in  order  to  be  the  controlling  section,  less  than  400  square 
inches.  The  actual  area  of  the  outlet  was  256  square  inches, 
being  too  small  to  pass  the  gas  and  steam  as  fast  as  generated, 
and  the  air  necessary  for  the  combustion. 

EXPERIMENT  ON  REDUCTION  OF  OUTLET. 

An  experiment  was  made  marked  Wells'  (4),  in  which  the  out- 
let from  the  flues  was  reduced  until  it  began  to  sensibly  affect 
the  draught.  The  area  of  the  outlet  was  reduced  to  2-J  square 
feet,  and  the  tan  consumed  \  of  a  cord  per  hour,  containing  (at 
the  temperature  of  the  chimney)  : 

Steam 100,000  cubic  feet  per  cord 

Gas  and  air 120,000  cubic  feet  per  cord 

Carbonic  acid  and  air 240,000  cubic  feet  per  cord 


460.000  cubic  feet  per  cord 

being  nearly  2,300  cubic  feet  per  minute.  The  furnace  was  fed 
every  15  minutes,  and,  therefore,  the  charge,  1-12  of  one  cord, 
containing  : 

Steam 8,300  cubic  feet 

Combustible  gas 3,000  cubic  feet 

11,300  cubic  feet 

or  enough  to  completely  fill  all  passages  for  egress  from  furnace 
for  4J  minutes.  If  the  gas  were  all  driven  from  the  tan  during 
this  time  all  passages  for  egress  would  be  filled,  no  air  could 
enter,  and  all  combustible  gas  must  be  wasted,  and  the  loss 
would  be,  as  before,  about  25  per  cent. 

If  the  period  of  drying  of  tan  extended  from  time  of  feeding 


4:3 


until  the  time  of  feeding  again,  and  the  gas  and  steam  were  ex- 
pelled uniformly,  the  loss  would  be  zero. 

I  judge  from  the  appearance  of  the  fire  that  the  time  occupied 
by  the  gas  and  steam  in  perfectly  leaving  the  tan  was  about  10 
minutes,  and  that  therefore  the  loss  was  less  than  10  per  cent. 
The  actual  loss  from  experiment  was  about  6  per  cent. 

The  controlling  section  was  found  to  be  at  the  ash  pit  100 
square  inches,  and  the  section  that  commenced  to  affect  the 
draft  at  the  chimney  360  square  inches,  from  which  I  infer  that 
in  order  to  perfectly  consume  the  tan  in  a  furnace  fed  from  the 
front,  or  with  two  feed  holes,  the  areas  of  opening  for  air  must 
be,  per  pound  of  dry  tan  burned  per  hour  (with  a  chimney  80 
feet  high  and  a  temperature  of  500°)  : 

Ash  pit 0.20  square  inches 

Outlet  of  furnace 2.50  square  inches 

Entrance  to  chimney 1.00  square  inches 

Entrance  to  flues  (when  one  oven  is  connected  to  boiler) 1.50  square  inches 

and  that  an  area  of  the  following  area  per  pound  of  dry  tan  per 
hour  will  be  the  controlling  section,  and  will  limit  the  rate  of 
combustion  : 

Ash  pit 0.20  square  inches 

Outlet  of  furnace 0.90  square  inches 

Entrance  to  chimney 0.50  square  inches 

Entrance  to  flues 0.60  square  inches 

In  the  old  Thompson  furnace  at  Wells'  there  were  4  openings 
from  the  oven  into  the  combustion  chamber,  each  said  to  be  18 
inches'  square — 1,300  square  inches.  They  used  to  burn  600 
pounds  of  tan  per  hour  ivith  difficulty.  This  explains  why  they 
had  so  much  trouble  to  keep  steam.  They  need  all  the  steam 
coming  from  500  pounds  of  tan  per  hour,  and  if  they  waste  all 
the  combustible  gas  they  must  burn  1,000  per  hour.  This  would 
be  at  the  rate  of  1  3-10  square  inch  of  outlet  for  every  pound  of 
dry  tan,  or  nearly  the  limit  of  the  furnace  in  good  weather  under 
favorable  circumstances.  If  for  any  reason  the  maximum  per- 
formance is  suspended  for  a  few  minutes  the  tannery  must  stop 
and  wait  for  steam.  This  they  often  had  to  do.  Probably  their 
whole  difficulty  would  be  overcome  by  enlarging  the  outlets  from 
the  furnace  to  2J  square  feet  each.  I  have  no  doubt  this  may 
be  done  to  advantage  in  many  existing  Thompson  furnaces. 

At  Brackneyville  the  area  of  outlet  from  furnace  was  1  \  square 
inches  per  pound  of  dry  tan  per  hour,  being  too  small.  The 
loss  by  combustible  gas  here  was  5  per  cent,  of  heat  utilized. 

The  economy  of  Weed's  furnace  would  probably  be  increased 


4:3 

*JC, _ 

f 

25  per  cent,  by  either  doubling  the  area  of  outlet  from  the  oven 
or  by  reducing  the  consumption. 

The  rapidity  of  drying  and  coking  the  tan  in  the  furnace  de- 
pends upon  the  surface  of  the  tan  exposed  to  the  radiant  heat 
(being  equal  to  the  grate  surface  in  a  furnace  fed  from  the  front, 
and  to  the  entire  surface  of  the  cones  in  the  furnace  fed  from 
the  top),  while  the  amount  of  water  to  be  given  off  depends 
upon  the  rate  of  combustion,  and  the  portion  of  the  time  occu- 
pied in  the  drying  of  the  tan  upon  the  thickness  of  the  bed  on 
the  grate.  Thus  the  water  and  gas  will  be  given  off  more  uni- 
formly during  the  whole  process  of  combustion  if  the  fire  is 
carried  on  the  grate  12  inches  thick  than  8  inches,  and  if  the 
hight  of  the  cone  in  a  furnace  fed  from  the  top  is  6  feet  than  4J 
feet.  The  hight  of  the  cone  being  limited  by  the  size  of  the 
oven,  it  follows  that  for  an  oven  6  feet  in  diameter  the  areas  of 
outlet  may  be  smaller.  It  is  for  this  reason  I  judge  that  the 
Hoyt  furnace  at  Wilcox  was  able  to  burn  at  the  rate  of  one 
pound  of  dry  tan  to  1.0  square  inch  of  flue  area,  and  to  6-10 
square  inch  of  chimney  area,  both  being  less  than  the  limiting 
areas  for  a  furnace  4J  feet  in  diameter,  or  a  Crockett  furnace, 
without  loss,  although  it  will  be  noticed  that  the  heat  accounted 
for  in  the  second  experiment  is  more  than  in  the  first,  indicating 
better  combustion  at  the  slower  rate.  Also  when  there  are  four 
feed  holes  there  is  a  greater  chance  of  one  cone  being  freshly 
fed  and  giving  off  steam  and  gas  all  the  time.  If  there  were 
cones  enough  the  cross  areas  of  outlet,  chimney  and  flue  might 
be  reduced  to  the  limiting  areas  without  loss.  I  think  that  suf- 
ficient air  for  combustion  of  the  gases  would  enter  the  Thomp- 
son oven  in  the  portion  of  the  rectangular  grate  left  uncovered 
by  the  circular  bases  of  the  cones,  for  these  cones  are  spaced 
further  apart  in  the  Thompson  furnace  iu  proportion  to  the  hight 
than  in  the  Hoyt.  The  portion  of  the  grate  left  uncovered,  or 
covered  very  thin,  would  remain  or  soon  become  bare.  These 
openings  fulfill  the  same  part  as  the  holes  in  the  "  Crockett  "  fire. 

The  furnace  at  Binghamton  was  arranged  so  that  the  ovens 
were  all  connected  in  pairs,  the  furnace  at  Brackneyville  so  that 
one  pair  was  connected  and  one  single,  and  the  furnace  at  Wil- 
cox so  that  each  oven  was  single.  The  combustion  at  Wilcox 
was  sensibly  perfect,  while  at  Binghamton  it  was  very  imper- 
fect. There  is  no  escape  from  the  conclusion  that  connecting 
the  furnaces  together  was  at  least  of  no  benefit.  The  same  may 
be  said  of  the  hot  ash  pit. 
I 


It  appears  from  the  figures  given  in  report  that  the  combus- 
tion was  more  perfect  at  Brackneyville,  and  that  also  the  sup- 
ply of  air  per  pound  of  tan  was  most : 

Weed.  Bracluieyvil'e. 

Percentage  of  total  heat  in  bark  lost  by  imperfect  combustion 9.0  2.4 

Pounds  of  air  supplied  per  pound  of  dry  tan 9.1  12. 

Per  cent,  of  air  in  excess  of  that  necessary  for  combustion 50.  75. 

It  would  appear  from  these  figures  that  it  was  necessary  to 
supply  1|  as  much  air  to  the  Thompson  furnace  as  was  necessa- 
ry for  combustion,  and  only  1  4-10  times  as  much  as  was  neces- 
sary for  combustion  to  the  Hoyt.  I  believe  this  is  actually  the 
case,  not  because  of  any  of  Thompson's  patents,  but  because  in 
the  Hoyt  furnace  there  are  four  feed  cones,  and  the  air  and  com- 
bustible gas  have  a  better  opportunity  to  be  thoroughly  inter- 
mingled than  in  either  of  the  Thompson  furnaces  when  there 
were  only  two  feed  cones ;  also  because  a  greater  part  of  the  air 
in  the  Hoyt  furnace  is  admitted  directly  into  the  oven  above  the 
fire,  and  has  an  opportunity  to  mix  with  the  gas  and  consume  it, 
while  in  the  Thompson  furnace  it  must^rs^  pass  through  the  fire 
and  then  consume  -the  gas.  It  will  be  very  hard  to  get  a  suffi- 
cient supply  of  air  to  pass  through  the  fire  without  being  taken 
up  by  the  red-hot  embers.  I  doubt  very  much  whether  it  would 
be  possible  to  have  an  excess  of  75-100  of  the  air  taken  up  in 
the  oven  of  the  Thompson  furnace  as  built  at  Binghamton— 
that  is,  without  some  means  of  supplying  fresh  air  into  the 
combustion  chamber.  At  Brackneyville  air  was  supplied  to  the 
combustion  chamber  through  leaks  in  the  badly-fitting  door.  A 
few  holes  in  the  door  of  the  combustion  chamber  at  Weed's 
would  supply  the  air  necessary. 

Assuming,  then,  that  there  wall  be  required  in  a  Thompson  fur- 
nace with  two  feed  holes  1|  as  much  air  as  is  necessary,  or 
12  3-10  pounds  per  pound  of  dry  tan,  and  that  the  air  supply  in 
the  Crockett  furnace  must  be  1  6-10  times  as  much  as  in  the 
Hoyt,  or  16  pounds  of  air  per  pound  of  dry  tan,  the  maximum 
absolute  efficiency  of  the  three  furnaces  will  be  when  the  chim- 
ney gas  is  at  500°,  and  when  the  wet  tan  contains  62  per  cent, 
of  water : 

Hoyt 82.6  110.8 

Thompson 79.2  106.2 

Crockett '. 74.6  100.0 

In  this  comparison  each  furnace  has  been  taken  with  the  air 
supply  actually  found  by  experiment,  while  from  what  has  been 
said  it  appears  that  the  Crockett  furnace  will  only  need  13  pounds 
of  air  per  pound  of  dry  tan.  I  have  not  made  a  comparison  on 


45 

»JO_ . 

r 

the  basis  of  13  pounds  of  air  for  the  Crockett  furnace  because  it 
was  not  an  experimental  determination,  and  may  be  open  to  crit- 
icism. 

Nevertheless,  I  have  no  doubt  that  if  each  furnace  were  pro- 
portioned in  the  best  manner,  and  the  walls  tight,  there  would 
only  be  required  13  pounds  of  air  per  pound  of  dry  tan,  when 
the  relative  efficiencies  would  be  : 

Hoyt 105.4 

Thompson 101.2 

Crockett 100.0 

The  best  and  an  almost  perfect  result,  has  been  obtained  in  a 
furnace  having  an  open  backed  single  oven,  with  a  cool  ash  pit. 
The  results  of  these  experiments  go  to  show  that  two  of  Thomp- 
son's claims,  namely  :  the  hot  ash  pit  and  the  reduced  outlet 
from  the  furnaces  are  absolutely  injurious,  and  that  the  third, 
{.'€.,  the  combination  of  a  pair  of  ovens,  is  at  most  of  no  value, 
for  a  practically  perfect  result  can  be  obtained  without  the  com- 
bination in  one  oven. 

It  has  been  customary  to  compare  experiments  on  these  fur- 
naces, by  adding  the  water  evaporated  in  the  boilers  to  the  water 
in  the  tan,  and  by  dividing  the  sum  for  one  furnace  by  the  sum  for 
the  other,  paying  no  attention  to  the  size  of  the  boilers,  the  method 
of  firing,  the  state  of  repair,  or  to  anything  but  the  water  evapo- 
rated and  the  tan  burned. 

The  results  thus  obtained  give  no  idea  of  the  relative  merits  of 
the  two  furnaces,  but  as  this  method  has  been  persistently  adhered 
to  in  former  reports,  such  a  comparison  is  made  here,  with  the 
following  results : 

The  average  of  all  of  each  kind Thompson.  .109 

Crockett....  110 
The  best  furnace  of  each  kind Thompson. .  99 

Crockett. . .  .100 
The  poorest  Crockett  with  the  best  Thompson.  .Thompson.  .137 

Crockett....  100 
The  poorest  Thompson  with  the  best  Crockett.  .Thompson. .  97 

Crockett....  100 

It  appears  that  by  comparing  in  this  way  and  selecting  ex- 
amples, any  result  from  a  superiority  of  37  per  cent,  to  an  inferi- 
ority of  3  per  cent,  may  be  obtained  for  the  Thompson,  while  the 
relative  efficiency  of  the  two  furnaces  as  shown  by  the  experi- 
ment is : 

Thompson 106 

Crockett 100 

The  results  of  these  experiments  indicate  that  for  a  furnace 
having  a  chimney  80  feet  high,  and  discharging  the  gas  at  a  tern- 


4:0 


perature  of  600°,  the  atmosphere  being  60°,  and  the  tan  being  well 
leached  and  containing  62  per  cent,  of  water,  compared  with  the 
residue  dried  at  110°  C.,  as  follows  : 


CALORIFIC   POWER. 


One  pound  of  wet  tan  will,  when  perfectly  consumed,  evaporate 
2  pounds  of  water  from  212°,  or  5  pounds  from  212°  per  pound 
of  diy  tan,  being  about  |  of  the  water  that  would  be  evaporated 
by  one  pound  of  the  dry  portion  or  ordinary  pine  wood. 


POOREST  PERFORMANCE. 


One-third  of  the  heat  may  be  wasted  by  careless  firing  or 
inferior  design  of  oven,  and  that  there  will  be  evaporated  under 
these  circumstances  2^  pounds  of  water  for  each  pound  of  the  dry 
tan. 

CROSS  SECTION  OF  FLUES. 

That  in  order  to  insure  perfect  combustion,  the  area  of  egress 
for  the  gas  from  the  boiler  must  exceed  that  necessary  for  coal  or 
wood,  and  must  be  for  an  oven  with  two  feed  holes,  or  fed  from 
the  front  at  least,  for  each  pound  of  dry  tan  burned  per  hour  at 
the 

Outlet  of  oven 2.50  square  inches 

Entrance  to  flues 1.50  square  inches 

Entrance  to  chimney 1.00  square  inches 

and  that  the  draught  must  be  controlled  at  the  ashpit  door. 

When  two  ovens  are  connected  to  one  boiler,  or  when  one  oven 
has  four  feed  holes,  the  areas  of  egress 'per  pound  of  dry  tan  per 
hour  may  be  : 

Entrance  to  flues 1.00 

Entrance  to  chimney 0.75 

LEAST  SECTION  OF  FLUES,  ETC. 

When  the  fire  is  forced  to  the  uttermost,  the  number  of  inches 
of  sectional  area  at  the  various  points  in  the  passage  of  the  gas 
from  the  ash  pit  to  the  chimney  top  will  be  : 

Entrance  lo  ash  pit 0.20 

.  Outlet  to  furnace 0.90 

Entrance  to  flues 0.60 

Entrance  to  chimney 0.50 

COMBUSTION  PER  SQUARE  FOOT  OF  GRATE. 

Under  the  above  circumstances  the  tan  will  burn  at  the  rate  of 
10J  pounds  of  dry  tan  per  square  foot  of  grate  per  hour  at  least, 
and  possibly  more.  It  is,  however,  favorable  to  economy  to  have 
a  slow  combustion  per  square  foot  of  grate  surface,  not  exceedin 


17 

b^y — 

5  pounds  per  square  foot  of  grate  per  hour,  and  probably  eyen 
slower. 

HEATING  8UBFACE. 

There  will  be  required  in  the  Crockett  furnace  when  burning  5 
pounds  of  dry  tan  per  square  foot  of  grate  surface  per  hour  1^ 
feet,  and  in  the  Hoyt  furnace  1^  feet  of  heating  surface  for  each 
pound  of  dry  tan  burned  per  hour,  being  in  the  last  case  about  the 
same  proportion  as  would  be  required  for  a  furnace  burning  coal 
or  wood  to  furnish  about  the  same  amount  of  heat. 

Although  the  heating  surface  required  for  coal  or  wood  is  the 
same  as  for  tan,  the  cross  section  of  the  flues  is  required  to  be 
about  double,  and  the  grate  surface  about  four  times  as  much,  so 
that  if  the  same  boilers  which  originally  could  just  furnish  steam 
with  wood  or  coal  were  attached  to  a  furnace  burning  tan  the 
chimney  would  have  to  be  much  higher. 

AIR  SUPPLY. 

The  least  air  used  in  any  of  the  experiments  when  the  combus- 
tion was  complete  was  10  pounds  per  pound  of  dry  tan,  or  an 
excess  over  that  actually  necessary  of  40  per  cent.,  about  the  same 
as  is  found  in  a  coal  fire. 

RESULTS   OBTAINED. 

That  when  these  proportions  are  observed  the  combustion  was 
found  to  be  perfect  in  the  Hoyt  and  Crockett  oven,  and  would  un- 
doubtedly be  perfect  in  the  Thompson  if  the  ash  pit  was  cleared 
out  and  the  area  of  outlet  at  the  back  of  the  furnace  enlarged,  and 
that  while  it  may  be  the  results  of  the  patented  furnace  may  become 
with  skillful  management  and  design  equal  to  the  unpatented,  it 
appears  that  the  unpatented  furnace  is  practically  perfect,  and 
that  therefore  the  patented  attachments  have  no  value  at  all. 

THERMAL  EQUIVALENT   OF  BARK. 

The  numbers  assumed  for  the  thermal  equivalent  of  bark  dried 
at  110°  C.  (unleached  8J,  leached  9.00  pounds  of  water  from  212°) 
are  probably  comparatively  corn  ct.  Nevertheless,  from  the  fact 
that  in  the  two  experiments  at  Wilcox  the  heat  accounted  for 
overruns  these  numbers,  while  at  Wells'  (1)  and  (2)  it  reaches  it, 
there  being  no  margin  for  incomplete  combustion  and  radiation. 
I  am  of  the  opinion  that  the  thermal  equivalent  of  hemlock  bark, 
probably  from  the  extra  amount  of  resin  it  contains,  is  more  than 
these  numbers,  and  is  at  least  9  pounds  of  water  from  212°  for  the 
unleached  bark  dried  at  110°  C.  and  9J  pounds  for  the  leached 
bark. 


The  details  of  the  drying  of  the  tan,  and  also  of  a  very  elegant 
experiment  for  drawing  and  analyzing  the  chimney  gas,  devised 
and  executed  by  my  associate,  Mr.  J.  K.  Bees,  were  under  his 
especial  charge,  and  are  properly  the  subject  of  an  independent 
report.  Very  respectfully, 

THEBON  SKEEL. 


i*  of  Ovens  and  Boilers. 


Location  of  Furnace         

Great  Bend, 

Webb's  Mills 

Br'kneyville, 

Binghamton 

Wilcox, 

N.  Y. 

N.  Y. 

N.  Y. 

N.  Y. 

Pa. 

Name  of  owner  

Stevens. 

Wells. 

Weed. 

Schultz. 

Kind  of  oven  

Crockett. 

Crockett. 

Thompson. 

Thompson. 

Hoyt. 

Kind  of  boiler  

Flue. 

Flue. 

Flue. 

Tubular. 

Flue. 

Material  of  chimney 

Iron 

Iron. 

Iron. 

Brick. 

Brick. 

Hight  of  chimney  above  grate,  ft.  . 

74 

80 

94 

109 

Grate  surface,  sq.  f  t  

60 

78 

162 

243 

192 

Heating  surface,  sq.  ft  

400 

830 

480 

2,000 

950 

Cross  area  of  flues  or  tubes,  sq,  ft.  . 
Cross  area  of  stack,  sq.  ft  

2.50 
5.40 

5.54 
5.24 

3.14 
4.90 

8.33 
9 

6.4 
16  for  4  ovens 

PBOPOBTIONS. 

Grate  surface  to  heating  surface.  .  . 

1  :  6.66 

1  :  16.4 

1  :2.9 

1  :8.2 

1  :  4.75 

Grate  surface  to  cross  area  tubes.  .  . 

24  :  1 

14  :1 

51  :  1 

29  :1 

30  :1 

Grate  surface  to  cross  area  chimney 

11  :1 

33  :  1 

33  :  1 

27  :1 

24  :1 

Statement  of  Means  and  Totals  of  Observations  and  Measurements. 


Date  of  Experiment  

Sept. 

Sept. 

Sept, 

Sept. 

Oct. 

Oct. 

Oct. 

Nov. 

NOT. 

Name  of  owner  of  furnace  ...  . 

Stevens 

Wells 

Brack 

Weed 

Wells 

Wilcox 

Wilcox 

Wells 

Wella 

Number  of  experiment  I 
Duration  of  experiment,  hours 

I. 

12 
60 

I. 

12 
55 

I. 

12 

73 

I. 

12 
67 

II. 

12 

29 

I. 

24 
75 

II. 

24 
75 

III. 
12 
65 

IV. 
12 

30 

TOTALS. 

Pounds  of  wet  tan  consumed.  . 

20,129 

26,814 

10,382 

36,138 

17,282 

62,123 

46,612 

17,027 

16,512 

Pounds  of  ashes  and  refuse  .  .  . 

204 

265 
26  549 



Pounds  of  feed  water  

16,760 

27,920 

14,430 

70,035 

18,560 

98,018 

81,250 

24,570 

22,365 

TEMPEBATtTBE. 

1  8"6° 

2,000° 

1,900° 

2,000° 

2,000° 

1,900° 

1,900° 

""50° 
700° 

'  '  70° 
580  D 

1,900° 
50° 
580° 

1,900° 
65° 
510° 

"'5(P 
420° 

2,000° 
70° 
700° 

2,OTO° 
70° 

580° 

..  . 
30° 
490° 


30° 
455° 

140° 

59  3 

140° 

195° 

140° 

41° 

41° 

140° 

140° 

Ash  pit         .          

480°  545° 

700° 

1,500° 

1,500° 

70° 

480° 

700° 

Per  cent,  water  in  wet  spent 
tan  dried  at  110°  C  

61.5 

63.4 

59.0 

55.1 

62.8 

61.2 

61.2 

61.5 

62.3 

Percent,  ashes  and  refuse  — 

2.61        2.7 

Per  cent,  water  in  gr'n  ground 

(fine* 

!crs.  } 

WEIGHTS. 

Weight  cord  unleachedbark. 



2,582 

2,353 

J  fine  )  U  era  * 
(2418*     (2284S 

Weight  cord  leached  wet  tan. 
Weight  cord  leached  dry  tan.  . 

4,442 
1,710.2 

4,294 
1,571.6 

4,112 
1,686 
R.237 

4,270 
1,917.2 

4.225 

4.076 
1,581.9 

4,076 
1,581.9 

4,275 
1,645.9 

4,260 
1,606.0 

5O 


Mean   of  Observations  on  Apparatus   for  Detecting  Water  Entrained    in    Steam. 


Experiment  

Wells. 
(L) 

Brack- 
ney. 

Weed.  1  Wells. 

!  "•> 

Wil- 
cox. 

Number  of  hours  apparatus  was  in  use  
Mean  temperature  of  injection  
Mean  temperature  of  discharge  
Mean  temperature  of  worm  
Pounds  water  from  worm  per  hour  

5 

49.4 
99.1 
111 
99 
19.70 
55 

5 
57.25 
985 
102 
91.7 
21.75 
53 

6 
56.29 
104,61 
118.3 
94.4 
18.3 
71 

6 
48.8 
73.73 
74.9 
49.8 
19.625 
26. 

11 
40.9 
83.44 
92.80 
81.18 
20.125 

Pressure  of  steam  above  atmosphere  

Calculated  Results  From  Experiments. 


Name  of  furnace  

Stevens. 

Wells. 

Brack. 

Weed. 

Wells. 

Wilcox. 

Wilcox. 

Wells. 

Wells. 

Number  of  experiment  

I. 

1. 

I. 

I. 

II. 

I. 

II. 

III. 

IV. 

Perc«ntage  of  water  in  tan  

61.5 

63.4 

59.0 

55.1 

62.8 

61.2 

61.2 

61.5 

62.3 

Percentage  of  solid  matter  in  tan  . 

38.5 

36.6 

41.0 

44.9 

37.2 

38.8 

38.8 

385 

37.7 

Weight  of  cord  of  wet  tan  
Weight  of  dry  portion  of  do  
Weight  of  insoluble  portion  do.  .  .  . 
Weight  of  portion  lost  by  boiling.  . 

4,442 
1,710 
1,626 

84 

4,294 
1,571.6 
1,478 
93.6 

4,112 
1,648.9 
1.536 
112.9 

4,270 
1,917.2 
1,509 
408.2 

4,225 
1,571.7 
1,424 
147.7 

4,076 
1,581.9 
1,484 
97.9 

4,076 
1,581.9 
1,484 
97.9 

4,275 
1,645.9 

4,260 
1,606.0 

HOURLY  QUANTITIES. 

Pounds  of  wet  tan  burned  
Pounds  of  dry  tan  burned  

1,675 
645 

2,235 

818 

865 
355 

3,011 
1,352 

1,440 
536 

2,588 
1,004 

1,942 
754 

1,419 
546 

1,376 
519 

Pounds  of  wet  tan  per  sq.  ft.  grate. 

27.9 

28.7 

5.4 

12.4 

18.4 

13,4 

10.1 

18.2 

18.0 

Pounds  of  dry  tan  per  sq.  ft.  grate 

10.7 

10.5 

2.2 

5.6 

6.8 

5.2 

3.9 

6.1 

6.0 

Pounds  of  wet  tan  persq.  ft.  heat- 

ing surface  
Pounds  of  dry  tan  per  sq.  ft.  heat- 

4.19 

2.69 

1.81 

1.50 

1.72 

2.72 

2.C4 

1.71 

1.66 

ing  surface      ...                .... 

1.61 

0.98 

0.73 

0.67 

0.64 

1.05 

0.79 

0.66 

0.63 

Pounds  of  wet  tan  per  sq.  ft.  cross 

section  of  tlues  

671 

404 

270 

360 

262 

404 

303 

258 

550 

Pounds  of  dry  tan  per  sq.  ft.  cross 

section  of  flues  

258 

147 

110 

160 

98 

157 

119 

99 

207 

Pounds  water  evaporated 

1,397 

2,327 

1  203 

5836 

1,547 

4  084 

3  385 

2,048 

1,864 

Pounds  water  entrained  with  steam 

'  33 

'  95 

'188 

'  55 

*s.h.24° 

*s.h'.24° 

ECONOMIC      PERFORMANCE- 

POUNDS  OF    WATER  EVAPORATED. 

Per  pound  wet  tan  from  feed  
Per  pound  dry  tan  from  feed  

0.833 
2.161 

1.041 

2.809 

1.390 
3.329 

1.938 
4.319 

1.074 

2.887 

1.523 
3925 

1.750 
4.510 

1.443 
3.747 

1.355 
3.594 

Per  pound  wet  tan  from  212°  
Per  pound  dry  tan  from  212°  
Pounds  water  evaporated  from  212C 

0893 
2.319 

1.117 
3.025 

1.680 
4.098 

1.988 
4,529 

1.192 
3.204 

1.790 
4.613 

2.058 
5.304 

1.605 
4.168 

1.480 
3.954 

per  sq.  ft.  heating  surface  

3.79 

3.36 

3.00 

2.92 

2.25 

5.19 

4.26 

2.73 

2.50 

Per  cent,  of  carbonic  acid  in   dry 

gas  by  volume  

7.5 

8.9 

11  1 

8.2 

Per  cent,  of  oxygen  in  dry  gas  by 

volume  

14.9 

13.3 

10.6 

14.7 

Pounds  air  per  pound  dry  tan  cal- 
culated from  velocity  of  smoke.  . 

22 

18 

13 

10 

16 

..... 

DISTRIBUTION    OF    HEAT    OF   ONE 

POUND  OF  DRY  TAN  IN  POUNDS  OF 

WATER  EVAPORATED  FROM  212°. 

Gas  passing  up    chimney  heated 
from  temperature  of  atmosphere 
to  temperature  of  chimney  
Water  in  tan  evaporated  from  68° 

2.94 

2.40 

1.33 

1.73 

1.40 

1.96 

and  superheated  to  temperature 
of  chimney  

2.28 

1.91 

1.61 

2.19 

2.09 

2.07 

Water  evaporated  in  boiler  from 

212° 

303 

4.01 

4  53 

4  61 

5.30 

4,17 

Water  of  combustion,  estimated.. 

045 

0.45 

0.50 

0.45 

(i.45 

0.45 

Sum  of  above  four  quantities  
Thermal  equivalent  of  tan  (cal).  .  . 

8.70 
9.0J 

8.77 
8.9 

7.97 
8.60 

8.98 
9.00 

9.24 
9.00 

8.65 
8.90 

Difference,    being    loss   from    all 

causes,  incomplete  combustion, 

radiation    etc 

030 

0.13 

—0.63 

0.02 

024 

—.25 

Available  heat  per  pound  of  dry  tan 
Absolute  efficiency  of  furnace  and 

6.72 

6.99 

6.99 

6.81 

6.91 

6.83 

boiler  

45.0 

57.3 

64.7 

678 

76.7 

61.1 

•Super-heated,  24°. 


REMARKS  ON  EXPERIMENTS. 


(J^rom  Note 

Made  an  experiment  on  Crockett  furnace  Sept  21  and  22.  Used 
bark  that  had  been  pitched  out  from  leaches  24  hours  before,  and 
had  been  draining  on  ground  during  that  time.  Tan  was  meas- 
ured in  box  and  each  box  weighed.  Furnaces  were  fired  by 
M.  A.  Stevens  in  the  usual  manner,  i.  e.,  furnace  was  fired  every 
10  minutes  nearly,,  tan  being  thrown  in  through  both  doors  and 
whole  surface  of  grate  covered  6  inches  or  8  inches  thick.  Con- 
siderable white  smoke  issued  from  the  stack  all  the  time,  but  most 
for  a  few  minutes  after  firing.  Temperature  of  crown  of  furnace 
near  fire  bridge  (perhaps  over  half  of  furnace)  was,  when  the  door 
was  opened,  a  dull  red  ;  soon  became  black  after  firing.  A  part 
of  unburned  tan  dropped  through  holes  in  grate  into  ash  pit  at  a 
bright  red  heat  and  slowly  consumed  there  without  blaze.  The 
temperature  of  ash  pit  was  found  by  thermometer  held  close  up 
under  grate  bars,  near  back  end,  480°-545°.  The  grates  were  of 
iron  and  had  been  in  use  8  years  ;  were  badly  warped,  and  cracks 
were  covered  over  with  fragments  of  iron  ;  it  was  through  these 
cracks  that  tan  fell  into  ash  pit.  There  must  have  been  consider- 
able heat  lost  by  radiation  from  brick  work  and  iron  uptake. 
Chimney  was  part  brick  and  part  sheet  iron.  Sparks  could  be 
seen  in  large  quantities  through  hole  cut  for  thermometer,  and 
once  were  seen  from  top  of  stack.  A  great  many  sparks  seemed 
to  leave  the  furnace  over  bridge  wall,  and  on  opening  back 
connection  doors  cinders  were  found  which  commenced  to 
consume  as  soon  as  air  was  admitted.  Feed  water 

was  heated  by  passing  through  pipe  surrounded  by  steam ; 
was  found  to  be  nearly  1igM.  Temperature  of  feed  150°, 
well  water  54°.  Tally  of  barrels  of  water  and  boxes  of 
tan  were  kept  by  two  persons  independently.  Water  was 
started  at  three  cocks  and  brought  to  this  point  at  end* 
Sample  of  tan  was  taken  from  various^  parts  of  heap  at 
8  p.  m.  Zinc  was  not  melted  in  chimney  or  ash  pit.  Copper 


was  not  melted  in  furnace.  Silver  was  melted  in  furnace.  There 
were  many  crevasses  in  brick  work  around  boiler  which  emitted 
smoke  during  some  portion  of  time,  and  which  in  back  connection 
were  surrounded  by  deposit  of  "coal  tar."  Dimensions  of  box 
in  which  tan  was  measured  :  3  feet  6J  inchesX^  feet  3  inchesX 
2  feet  Oj  inch  ;  capacity,  16.2  cubic  feet. 


Made  experiment  on  Crockett  furnace  at  Webb's  Mills,  recently 
erected,  and  owned  by  Mr.  Wells.  Cone  grates  in  good  condition. 
*  *  *  Water  measured  in  barrels,  tan  measured  in  boxes. 
Tan  had  been  draining  in  leach  24  hours  before  and  was  pitched 
during  experiment ;  was  wheeled  100  feet  in  barrows,  and  then 
dumped  10  feet  to  fire  room  floor.  *  *  *  During  first  part  of 
experiment  damper  one-half  open  and  furnace  cool ;  ash  pit  door 
8  inches  open.  During  last  half  fires  thicker,  i.  e.,  6  inches  over 
crest  and  15  inches  over  hollow  of  bars ;  damper  open ;  ash  pit 
doors  2^  inches  open  ;  furnace  much  hotter  ;  steam  variable,  from 
45  to  65  pounds.  Stack  of  sheet  iron.  Feed  water  passed  through 
heater  said  and  believed  to  be  tight.  Pumps  worked  all  time. 
Water  supplied  to  barrels  by  centrifugal  pump.  Sides  of  furnace 
and  boiler  enclosed  by  walls  of  house.  Tan  apparently  wetter  than 
at  Great  Bend  and  coarser.  Boilers  apparently  good.  Gases 
drawn  every  hour.  *.*".-*  Engine  running  all  night,  blowing 
off  occasionally.  Water  carried  during  experiment  at  first  gauge, 
but  commenced  and  ended  at  second  gauge.  Arches  were  noticed 
toward  the  end  to  be  bright  red  before  firing.  Seams  below  the 
surface  remaining  hot  when  arches  were  black  after  firing.  Weight 
of  a  barrel  of  water,  315  pounds.  Dimensions  of  box  for  measur- 
ing tan,  3  feet  2  inchesX2  feet  3|-  inchesXl  foot  11  inches  ; 
capacity,  13.78  cubic  feet. 


Made  experiment  on  furnace  at  Bingharnton,  Sept.  29,  9  a.  m. 
till  9  p.  m.  Ovens  were  fed  with  tan  that  had  drained  36  hours, 
and  was  pitched  continuously  during  experiment.  Tan  weighed 


53 

^__ 

i 

and  measured  as  in  other  experiments.  Water  measured  in  casks. 
The  weight  of  water  at  56°  necessary  to  fill  cask,  358  pounds. 
Temperature  of  water  when  measured  during  experiment,  205°. 
Had  counter  on  pump.  Pump  delivered  a  varying  volume  of 
water,  depending  upon  the  depth  of  water  over  the  suction  pipe. 
Priming  determined  in  the  usual  way.  Air  clear,  wind  south  and 
fresh.  No  smoke  from  the  stack  at  any  time.  Never  melted 
copper  in  combustion  chamber.  Silver  melted  easily ;  silver 
melted  in  ash  pit  when  held  close  to  surface  of  embers.  Ash  pits 
were  not  cleaned  during  the  experiment  except  No.  2  oven.  Back 
connection  doors  showed  dull  red  in  the  dark.  Dimensions  of  box 
for  measuring  tan,  2  feet  8  inchesX2  feet  10  inchesX^  feet  4J 
inches ;  capacity,  17.8  cubic  feet. 

Dampers  wide  open  all  the  time.  No  smoke  from  chimney. 
Time  of  smoke  reaching  chimney  top  from  combustion  chamber, 
No.  1  and  2  oven,  10  seconds. 


Made  experiment  on  Thompson  furnace,  Sept.  25-26,  from 
8  p.  m.  till  8  a.  m.  Tan  used  measured  in  a  box  and  weighed  on 
scales.  About  one-third  of  the  tan  had  been  over  the  oven  some 
hours  (at  least  twelve)  before  experiment  commenced;  balance 
shoveled  from  the  leach  about  eight  hours  before.  These  two 
kinds  of  tan  were  mixed  by  shoveling  from  one  end  of  the  fire 
room  to  the  other  before  experiment  commenced.  Whenever 
weight  of  box  of  tan  in  log  is  marked  (*)  signifies  that  aboxfull  had 
been  taken  from  top  of  oven  ;  others  were  taken  from  heap  not  on 
top  of  oven.  Ovens  were  kept  buried  about  three  feet  deep  in  wet 
tan  during  whole  experiment.  Ash  pits  were  not  cleaned  out,  as 
owners  said  they  could  not  keep  up  steam  without  cinders  in 
them.  Boilers  connected  to  brick  pier  supporting  chimney 
through  sheet  iron  front  connection.  Wet  tan  laying  against  this 
connection  took  fire  and  burned  with  flame  during  whole  experi- 
ment. Made  sure  that  the  blow-off  valve  was  not  leaking  by 
filling  it  with  tan.  Silver  was  melted  in  one  flue  leading  from  one 
pair  of  ovens  but  not  from  other.  Fires  on  being  examined 
seemed  to  be  equally  hot.  Furnace  was  fired  every  2}  hours, 
nearly,  through  holes  farthest  from  the  door,  and  every  1£  hours 


54: 


through  holes  nearest  to  door.  All  holes  in  all  furnaces  in  same 
position  were  fired  at  once,  i.  e.,  all  holes  nearest  to  boiler  every 
2J  hours,  and  all  holes  furthest  from  boiler  every  1J  hours.  Fur- 
nace doors  had  no  holes  in  them  and  were  kept  tightly  closed  and 
luted  with  fire  clay.  Ash  pit  doors  were  of  sheet  iron,  about  2 
feet  square,  and  were  kept  so  as  to  expose  an  opening  for  the 
passage  of  air  of  about  40  square  inches  to  each  oven.  Glass 
water  gauge  in  chimney  showed  one-half  inch  ;  did  not  fall  when 
large  door  to  back  uptake,  2  square  feet,  was  opened.  Tempera- 
ture of  stack,  580°.  Seems  probable  that  almost  all  combustion 
took  place  on  surface  of  cone.  Amount  consumed  in  ash  pit 
small.  Temperature  of  ash  pit  600°.  Water  was  measured  in 
barrels  and  passed  into  tank  by  three  men  with  pails.  Tally  was . 
kept  by  two  men  independently.  Chimney  gases  were  drawn 
every  hour  till  4  a.  m.  Experiment  on  velocity  of  air  in  stack 
was  made  with  coal  smoke.  Time  required  to  reach  chimney  top 
from  combustion  chamber  was  :  10,  11,  10,  11,  12,  11J,  9,  9,  9,  9, 
9  seconds ;  mean,  10.04  seconds.  Weight  of  a  barrel  of  water, 
390  pounds.  Flues  were  swept  before  experiment  commenced. 
Boilers  were  fed  by  injector  ;  no  heater  ;  drip  water  from  injector 
returned  to  tank.  Doors  around  the  furnace  and  cracks  were  all 
luted  with  blue  clay  and  ashes  before  experiment.  Holes  above 
the  furnace  were  kept  covered  with  tan,  and  covers  not  used. 
WTeather  rainy  during  the  night  and  damp  in  morning.  Air,  50°  ; 
boiler  room,  70°.  Dimensions  of  box  for  measuring  tan  :  2  feet 
1J-  inchesX2  feet  8|  inchesX2  feet  1\  inches  ;  capacity,  14.69. 

THEEON  SKEEL. 


56 


58 


'Fici.  1. 


THOMPSON  FURNACES. 


59 


The  Moses  Thompson  Patent  for  Wet  Tan 
Burning  Furnaces. 


(Extracts  from  Patent,  showing    Claim  and  manner  of  icorking 

Furnaces.) 

SUBMITTED  BY  J.  S.  SCHULTZ,  J.  B.  HOYT  AND  OTHERS. 

Fig.  1  is  a  horizontal  section  of  a  furnace  constructed  according 
to  my  invention. 

Fig.  2  is  a  vertical  section  of  the  same  in  the  line  x  y  of  Fig.  1. 
*  *  *  *  #  -x-  #  * 

The  main  object  of  my  invention  is  to  effect  the  more  economi- 
cal use  for  fuel  of  tan  bark,  bagasse,  or  other  trashy  matters  in  a 
wet  state,  or  very  green  or  wet  wood. 

It  is  also  applicable  to  the  burning  of  fuel  of  that  or  other  de- 
scriptions in  a  dry  state  ;  but  when  the  fuel  is  dry  it  is  much  less 
useful,  and  I  do  not  claim  its  application  thereto. 

The  nature  of  my  invention  consists  in  the  employment,  in  the 
manner  hereinafter  described,  of  a  series  of  fire  chambers  ar- 
ranged side  by  side  or  in  any  convenient  way,  to  admit  of  the 
whole  series  communicating  with  the  same  heating  flue,  which 
said  fire  chambers  are  furnished  with  dampers  by  which  their  re- 
spective communications  with  the  flue  and  the  ash  pit  may  be 
closed  or  opened  at  pleasure. 

This  arrangement  is  for  the  purpose  of  enabling  the  process  of 
heating  the  fuel  to  an  intense  degree  in  a  nearly  air-tight  chamber, 
and  then  admitting  a  free  supply  of  air  to  promote  its  rapid  com- 


60 


bustion,  to  be  conducted  without  interruption  to  the  operations 
which  the  heat  generated  is  intended  to  effect. 

To  enable  others  skilled  in  the  art  to  make  and  use  my  inven- 
tion, I  will  proceed  to  describe  its  construction  and  operation. 

The  furnace  shown  in  the  drawings  has  three  fire  chambers,  A, 
A  \  A ' '.  Three  is  the  number  shown,  as  I  consider  that  number  in 
most  cases  to  be  the  best  adapted  for  practical  operation.  The 
fire  chambers  are  of  square  but  may  be  of  other  form  with  grate 
bottoms,  B,  B  ',  B  ' ',  and  arched  tops.  They  are  separated  by  walls 
of  non-conducting  material,  and  lined  throughout  with  fire  brick. 
Each  is  provided  with  a  door,  C,  in  front  for  the  purpose  of  \  light- 
ing and  tending  the  fire,  with  an  opening,  D,  at  the  top,  for  the 
purpose  of  supplying  the  fuel  when  it  consists  of  tan  bark,  saw 
dust,  or  other  material  of  a  similar  nature,  and  with  an  opening, 
E,  at  the  back,  which  leads  to  the  flue,  F,  the  opening,  E,  being 
provided  with  a  damper,  K.  Each  fire  chamber  has  a  separate 
ash  pit,  G,  below  it,  which  is  furnished  with  a  door,  H,  to  regulate 
the  admission  of  air. 

The  flue,  F,  extends  across  the  back  of  all  three  fire  chambers, 
and  the  chimney  may  be  at  one  end  or  may  be  placed  in  the  rear, 
with  a  flue,  I,  leading  to  it  from  the  flue^  F.  If  the  furnace  is 
used  for  generating  steam,  the  best  place  for  the  boiler  will  be  in 
the  flue  I,  which  will  be  made  of  proper  size  to  receive  and  nearly 
surround  it.  If  used  for  other  purposes,  any  arrangement  may 
be  made  that  may  be  considered  best,  but  the  thing  to  be  heated 
ought  to  be  so  high  as  not  to  require  the  products  of  combustion 
to  descend  on  their  passage  to  it. 

The  mode  of  conducting  the  operations  of  the  furnace  is  as 
follows  : 

Fires  being  lighted  in  all  the  fire  chambers,  two  of  the  three 
have  the  doors,  H,  H,  of  their  ash  pits  closed,  and  the  dampers,  K, 
K,  so  nearly  closed  as  only  to  allow  a  sufficient  escape  of  the  gases 
generated  by  the  slow  combustion  which  then  goes  on  to  prevent 
explosion.  The  other  fire  chamber  in  the  meantime  has  the 
damper  K  open,  and  the  door  of  the  ash  pit  opened  far  enough  to 
admit  any  quantity  of  air  that  may  be  requisite  to  promote  such 
a  degree  of  combustion  in  the  chamber  as  may  be  necessary  to 
generate  the  amount  of  heat  required.  The  air  should  be  drawn 
in  (except  when  excluded)  by  natural  draft,  and  if  a  high  stack  be 
used,  there  should  be  a  damper  in  it  to  check  the  draft. 

When  the  fluel  in  the  open  chamber  is  reduced  to  a  desirable 
degree  that  chamber  is  closed  and  recharged,  and  another  opened 


61 


and  supplied  with  air  until  the  fuel  within  is  reduced,  when  it  is 
closed,  recharged,  and  another  opened,  each  in  its  turn  being 
opened  and  freely  supplied  with  air  to  generate  and  supply  the 
requisite  amount  of  heat,  while  the  others  are  closed  and  succes- 
sively supplied  with  fresh  wet  fuel  to  heat  and  decompose  the 
same  to  such  a  degree  as  is  desirable  before  allowing  rapid  com- 
bustion and  escape  of  the  heat  to  take  place. 

Each  fire  chamber  should  be  supplied  successively  with  fuel  at 
proper  intervals  by  any  convenient  means,  either  through  the  hole, 
D,  or  through  the  door,  C,  in  front,  just  before  closing  the  fire 
chamber. 

The  principal  advantage  of  a  furnace  and  process  of  this  de- 
scription consists  in  heating  and  decomposing  the  fuel  without 
any  further  loss  of  heat  than  is  absorbed  by  the  poor  conducting 
material  of  which  the  furnace  is  constructed,  to  such  a  degree  as 
will,  when  a  proper  supply  of  air  is  admitted,  cause  the  most  per- 
fect combustion  of  the  gases  and  smoke  to  be  effected.  This 
could  not  be  effected  in  a  single  fire  chamber  without  interruption 
to  the  proper  supply  of  heat,  but  when  two  or  more  fire  chambers 
are  employed  no  interruption  takes  place,  as  one  furnace  is  always 
in  full  operation.  Another  advantage  consists  in  always  holding 
a  certain  quantity  of  heat  in  reserve  in  the  closed  chambers, 
which  may  be  immediately  brought  into  action  by  opening  one  or 
more  of  the  chambers. 

A  similar  but  inferior  result  might  be  produced  by  having 
several  separate  grates  and  ash  pits  to  the  same  fire  chamber, 
^ach  grate  charged  successively,  and  its  ash  pit  for  a  time  closed, 
immediately  after  fresh  charging,  to  exclude  the  air. 

I  have  described  this  in  my  caveat  upon  which  this  application 
is  based,  but  do  not  use  it  because  of  its  inferiority  in  practice, 
although  it  involves  my  principle. 

After  ample  experiments,  I  have  discovered  that  any  results 
which  can  be  produced  by  the  use  of  dry  fuel  are  entirely  inferior 
to  mine  in  proportion  to  the  quantity  used,  and  that  results  like 
mine  can  only  be  attained  by  the  use  of  wet  fuel,  similar  to  what 
I  have  herein  mentioned,  fed  into  an  intensely  heated  chamber. 

Under  such  circumstances,  the  water  in  the  fuel,  in  the  presence 
of  the  carbonaceous  substances  in  the  furnace,  will  be  decom- 
posed, giving  its  oxygen  to  the  carbonaceous  matter,  dispensing 
with  a  draft  and  its  cooling  and  wasteful  influences,  and  rendering 
the  combustion  so  perfect  that  no  smoke  is  \isible. 

I  do  not  claim  the  within-described  arrangement  of  a  series  of 


fire  chambers  to  communicate  with  one  common  flue,  irrespective 
of  the  purpose  for  which,  and  the  manner  in  which,  I  employ  the 
said  arrangement. 

But  what  I  do  claim  as  my  invention,  and  desire  to  secure  by 
letters  patent,  is  : 

The  combustion,  for  the  purposes  of  a  high  degree  of  heat,  of 
bagasse,  refuse  tan,  saw  dust,  and  other  refuse  substances,  or  very 
wet  and  green  wood,  by  the  employment  of  a  series  of  fire  cham- 
bers, arranged  in  any  manner  substantially  as  described,  to  com- 
municate with  one  flue,  when  any  number  of  the  said  chambers 
are  nearly  closed  to  the  flue  and  to  the  admission  of  air,  when 
first  charged  as  described,  while  the  remaining  chamber  or  cham- 
bers is  in  free  communication  with  the  flue,  and  has  a  free  supply 
of  air  admitted,  and  each  chamber  in  its  turn  is  nearly  closed,  and 
then  opened,  and  has  air  admitted,  whereby  the  heat  required  is 
furnished  by  the  combustion  of  the  fuel  in  one  or  more  chambers, 
while  the  fuel  in  the  other  chamber  or  chambers  is  being  heated 
and  decomposed  to  a  desirable  degree,  as  herein  set  forth,  no 
artificial  blast  being  used. 


NOTE. — The  drawings  of  the  real  Thompson  furnace,  as  seen  on 
page  58,  and  as  described  on  the  three  following  pages,  will  suffi- 
ciently indicate  the  original  idea  of  the  patentee.  But  the  claim 
has  been  construed  by  the  Court  to  cover  the  structure  on  page 
55.  For  the  purposes  of  this  examination  the  legally  construed 
furnace  has  been  assumed  to  be  the  true  Thompson  furnace. 
There  are  not  over  three  or  four  real  Thompson  furnaces — as  indi- 
cated by  the  original  drawings  and  description — in  existence,  and 
they  give  very  inferior  results.  J.  S.  SCHULTZ. 


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